Stats

What percentage of people have blue eyes?

Roughly 8 to 10% of people worldwide have blue eyes. There is no global census of eye colour, so this is an estimate stitched together from regional surveys. Blue eyes are concentrated in Northern and Eastern Europe, where surveys put Estonia and Finland near 90%. Eye colour is not a simple recessive trait: a 2021 genome study found 61 genomic regions involved. Most blue-eyed people do share one variant near the OCA2 gene, estimated to have arisen 6,000 to 10,000 years ago.

What percentage of people are left-handed?

About 10.6% of people are left-handed, based on a 2020 meta-analysis covering 2.4 million people. The figure moves between 9% and 18% depending on how strictly you define it. Men are slightly more likely to be left-handed than women. Identical twins do not always share handedness, so genes are only part of the story.

What is the average height of a person worldwide?

For adults born in 1996, NCD-RisC estimates a world average of about 171 cm for men and 159 cm for women, so roughly 165 cm for both sexes combined. Dutch men are the tallest at 182.5 cm. Men are about 12 cm taller than women in every country. Average height rose by 5 to 20 cm over the 20th century, depending on the country.

What is the average BMI worldwide?

NCD-RisC put the global age-standardised mean BMI in 2014 at 24.2 for men and 24.4 for women, just inside the 'normal' range of 18.5 to 25. Averages hide the spread: several Polynesian and Micronesian countries have mean BMIs above 32, while parts of South and East Asia sit near 21 to 22. Global mean BMI has risen by about 2 units since 1975.

What percentage of people are natural redheads?

Natural red hair occurs in about 1 to 2% of people worldwide, making it the rarest hair colour. It is most common in Scotland and Ireland, where figures of roughly 10 to 13% are often quoted, though these rest on small surveys rather than a national count. Red hair is usually caused by two copies of variants in the MC1R gene, so both parents must carry one.

What percentage of people are colour blind?

About 8% of men and 0.5% of women of Northern European descent have some form of colour vision deficiency; rates are lower in other populations. The common types are red-green (deuteranomaly and protanomaly). The genes sit on the X chromosome, so men need only one faulty copy while women need two.

What percentage of births are twins?

About 12 in every 1,000 deliveries worldwide are twin births, roughly 1.2%, or about 1.6 million twin pairs a year. That is up by a third since the 1980s, mainly from fertility treatment and older mothers in richer countries. Identical twinning has stayed steady at about 4 per 1,000 deliveries.

What is the average shoe size worldwide?

There is no global survey of shoe sizes. Foot-measurement studies in Europe and North America put the average adult male foot at about 26 to 27 cm (roughly EU 42 to 43) and the average female foot at about 23 to 24 cm (EU 38 to 39). Foot length runs at about 15% of height, so 6 to 7 cm of extra height adds roughly 1 cm of foot.

What is the average IQ worldwide?

IQ tests are built so that the standardisation sample averages 100 with a standard deviation of 15, so the 'average IQ' is 100 by definition rather than by measurement. Raw scores rose about 3 points per decade through the 20th century (the Flynn effect), which is why tests are re-normed every 15 to 20 years. Country-level IQ comparisons are contested because sampling and test translation vary a lot.

How fast does the average person read?

A 2019 meta-analysis of 190 studies put average silent reading of non-fiction at 238 words per minute and fiction at 260 wpm for adult English readers. Claims of 'speed reading' at 700 wpm or more come with large losses in comprehension. Audiobooks are narrated at roughly 150 to 160 wpm, so most people read faster than they listen.

What is the average typing speed?

In an online study of 168,000 people, the average typing speed was about 52 words per minute; typical office workers fall in the 40 to 60 wpm range. The fastest participants used 'rollover' typing, pressing the next key before releasing the last. The Guinness-recognised record is 216 wpm, set by Stella Pajunas on an IBM electric typewriter in 1946.

What is the average human reaction time?

The median simple reaction time on the Human Benchmark browser test is about 270 ms across millions of attempts. Laboratory studies with calibrated hardware find 200 to 250 ms; most of the gap is screen and input lag. Reaction time is fastest in the twenties and slows gradually with age, by roughly 2 to 3 ms per year on choice tasks.

How fast does the average person speak?

Conversational English runs at roughly 120 to 180 words per minute, with most speakers near 150 wpm. Rates differ by language, but a 2019 study of 17 languages found that fast-spoken languages such as Spanish and Japanese pack less information into each syllable, so all of them convey about 39 bits per second. Auctioneers and some podcasters exceed 200 wpm.

How many friends can a human brain maintain?

Robin Dunbar proposed in 1992 that humans can maintain about 150 stable relationships, extrapolating from the link between neocortex size and group size in primates. The number nests into layers of roughly 5, 15, 50 and 150. A 2021 reanalysis found the primate data too noisy to pin down a human group size at all, so treat 150 as an order of magnitude, not a hard limit.

How much sleep do adults need?

The American Academy of Sleep Medicine and the Sleep Research Society recommend 7 or more hours a night for adults aged 18 to 60. Just over a third of US adults report sleeping less than 7 hours. In a 2010 meta-analysis, people sleeping under 6 hours had about 12% higher mortality than those sleeping 7 to 8 hours.

How many words does the average person know?

Tests on about 220,000 people found the average 20-year-old native English speaker knows roughly 42,000 lemmas (dictionary headwords), rising to about 48,000 by age 60. That works out to nearly two new words a day through childhood and school, then about one every two days for the rest of life.

What is the global median income?

The World Bank estimates the global median income or consumption at roughly $8 per person per day (2017 prices, adjusted for purchasing power), about $2,900 a year. Half the world lives on less than that. The global mean is about twice as high, because high earners in rich countries pull the average up.

What percentage of the world lives in extreme poverty?

In June 2025 the World Bank raised its extreme poverty line to $3.00 a day in 2021 prices. On that line about 10% of people, roughly 800 million, live in extreme poverty in 2025, down from about 38% in 1990. Progress has slowed sharply since 2019. On the old $2.15 line the 2024 figure was about 8.5%.

How much wealth do the richest 1% own?

The richest 1% of adults held about 47.5% of global household wealth in 2023, according to UBS. The World Inequality Report 2022 puts the top 10% at about 76% of wealth and the bottom half at about 2%. Different databases disagree on the exact split but agree on the shape: wealth is far more concentrated than income.

What percentage of income does the average person save?

The US personal saving rate averaged roughly 5 to 8% of disposable income through the 2010s. It jumped to about 32% in April 2020 when lockdowns stopped spending, then fell to a low near 2 to 3% in mid-2022. Germany's household saving rate is usually 10 to 11%; China's exceeds 30%.

How many billionaires are there in the world?

Forbes counted 3,028 billionaires in its April 2025 list, a record, with a combined net worth of about $16.1 trillion. That is roughly 0.00004% of the world's people. The United States had 902 billionaires, China 516 and India 205.

What is the average person's carbon footprint?

Fossil CO₂ emissions averaged about 4.7 tonnes per person worldwide in 2023. The United States emitted about 14 tonnes per person, India about 2. To keep warming near 1.5°C, UNEP estimates per-person emissions need to fall to roughly 2 to 2.5 tonnes by 2030.

What percentage of global energy comes from renewables?

Renewables generated about 30% of the world's electricity in 2023, up from around 22% in 2015, with hydro still the largest single source. But electricity is only about a fifth of final energy use. Heating, transport and industry are mostly still fossil-fuelled, so renewables cover roughly 13 to 15% of total energy.

How many languages are spoken in the world?

Ethnologue lists about 7,160 living languages and classes about 44% of them as endangered. The 'one language dies every two weeks' line traces back to a 1992 worst-case projection; the Catalogue of Endangered Languages counts about 3 to 4 extinctions a year, closer to one every three or four months. Just 23 languages account for more than half the world's population.

What is the most common name in the world?

No reliable global name register exists. Muhammad and its spellings are widely estimated at 150 million or more bearers, because of the Muslim tradition of naming sons after the Prophet; this is an extrapolation from national data, not a count. Among women, Maria and its variants are usually ranked first. Within single countries the data is far better: in England and Wales, Muhammad was the top boys' name in 2023.

Is there a most common birth month?

In the United States, August usually has the most births, with July close behind; August topped the table in 8 of the 11 years from 2010 to 2020. February has the fewest. The most common individual birthdays cluster in mid-September, about nine months after the December holidays.

What is the median age of the global population?

The world's median age is about 31 years (2024), up from about 22 in 1950. The spread is large: Niger's median age is about 15, Japan's about 49. The UN projects the global median will pass 36 by 2050 as populations in Asia and Latin America age.

What is the global average life expectancy?

Global life expectancy at birth reached 73.3 years in 2024, up from about 47 in 1950 and back above its pre-pandemic level of 72.6. Japan leads at close to 85. Record life expectancy in the best-performing country has risen about 2.5 to 3 months per year since 1840.

Is marriage becoming less common?

Yes. The US marriage rate fell from 9.8 per 1,000 people in 1990 to 6.1 in 2023 (6.3 in 2024, provisional). The share of US adults who are married fell from 72% in 1960 to about 50% today. Similar shifts to later and fewer marriages are seen across Europe and East Asia.

What percentage of people feel lonely?

In a 2021 Cigna survey, 58% of US adults said they felt lonely; the US Surgeon General called it an epidemic in 2023. In the UK, about 7% of adults say they feel lonely often or always. The often-quoted 'as deadly as 15 cigarettes a day' is a popularised reading of a 2010 meta-analysis, which found that weak social ties raise mortality risk by about 50%, comparable to well-known risk factors such as smoking and obesity.

How much time does the average person spend looking at screens per day?

Internet users spend an average of 6 hours 38 minutes a day online across all devices (early 2025), of which roughly 3 hours 45 minutes is on a phone. These are self-reported figures from GWI surveys, not measured screen time. Kept up for 60 adult years, 6.6 hours a day adds up to about 16 years.

How much time does the average person spend on social media per day?

People who use social media spend an average of about 2 hours 21 minutes a day on it (early 2025), slightly down from 2 hours 23 minutes a year earlier. Brazil is near the top at 3 hours 49 minutes; Japan is under an hour. Over a year, 2 hours 21 minutes a day adds up to about 36 full days.

How much does the average person sleep per night?

Sleep-tracking app data from Sleep Cycle puts average time asleep near 7 hours a night across tracked countries, with the Netherlands and the Nordics longest and Japan shortest. App users are not a random sample. US surveys find about a third of adults sleep under 7 hours, and most adults need 7 or more.

What percentage of people get enough exercise?

About 31% of adults worldwide, 1.8 billion people, did not meet WHO activity guidelines in 2022, up from 23% in 2010. The guideline is 150 minutes of moderate activity a week. In the US, about 47% of adults meet the aerobic guideline and about 24% meet both the aerobic and strength guidelines.

How many cups of coffee are consumed globally per day?

World coffee consumption is about 10.6 million tonnes a year (177 million 60-kg bags in 2024/25), which works out to somewhere between 2 and 3 billion cups a day depending on how strong you make it. Finland drinks the most per person, around 12 kg of beans a year. About two-thirds of US adults drink coffee daily. The line that coffee is 'the second most traded commodity after oil' is false; it is not even the top agricultural export.

What percentage of people don't drink alcohol?

About 56% of people aged 15 and over had not drunk alcohol in the previous 12 months in 2019, according to WHO. Abstention is highest in North Africa, the Middle East and South Asia, largely for religious reasons, and lowest in Europe. In the US, about 38% of adults say they do not drink.

What percentage of people are vegetarian or vegan?

There is no reliable global count. India has by far the highest share: 39% of adults called themselves vegetarian in a 2021 Pew survey, and 81% limit meat in some way. In the UK, YouGov tracking finds about 5% vegetarian and 2 to 3% vegan, figures that have barely moved since 2019. Most Western countries sit in the 2 to 10% range.

What percentage of Earth's oceans have been explored?

As of April 2026, 28.7% of the sea floor has been mapped at modern resolution, according to the Seabed 2030 project, up from about 6% in 2017. Only a small fraction of that has been seen directly by cameras or submersibles. The ocean covers 71% of the planet and averages about 3.7 km deep.

How many species have been identified on Earth?

A 2011 estimate put the number of eukaryotic species on Earth at about 8.7 million, give or take 1.3 million. The Catalogue of Life listed about 2.0 million living species as described by the end of 2024. Around 15,000 to 20,000 new species are named each year, so describing the rest would take centuries at the current pace.

How many humans have ever lived?

The Population Reference Bureau estimates that about 117 billion people have been born since modern humans appeared, counting from around 190,000 BCE. With 8.2 billion alive in 2025, about 7% of everyone who ever lived is alive now. The estimate rests on assumed birth rates for the 99% of human history with no records, so treat it as an order of magnitude.

How similar is human DNA to other species?

Humans and chimpanzees differ at about 1.2% of positions where their genomes line up, so about 98.8% identical; counting insertions and deletions widens the gap to around 4%. About 85% of mouse genes have a human counterpart. The 'half our DNA is shared with bananas' line refers to the share of human genes with some banana equivalent, not identical sequence. Only about 1.5% of the human genome codes for protein.

How many neurons does the human brain have?

The adult human brain has about 86 billion neurons and a similar number of non-neuronal cells, measured by counting cell nuclei in dissolved brain tissue. The cerebellum holds about 80% of the neurons but only 10% of the mass. Each cortical neuron connects to thousands of others, giving the brain on the order of 100 trillion synapses.

How many bacteria are in the human body?

A 2016 recount estimated about 38 trillion bacterial cells in a 70 kg man, against about 30 trillion human cells. That is a ratio near 1:1, not the '10 to 1' figure repeated for decades. Most of the bacteria live in the colon and weigh about 200 grams in total. The gut microbiome's genes outnumber human genes more than 100-fold.

How many times does the heart beat in a lifetime?

At a resting rate of 70 beats per minute the heart beats about 100,000 times a day, or roughly 2.7 billion times over 75 years. Across mammals, small animals have fast hearts and short lives, large animals the opposite, and the lifetime total comes out near 1 billion beats for most species. Humans are an outlier with about three times that.

Was Cleopatra closer in time to the Moon landing or the pyramids?

Cleopatra was born in 69 BC. The Great Pyramid of Giza was completed around 2560 BC, about 2,490 years before her birth. The Moon landing in 1969 came about 2,040 years after it. So she lived roughly 450 years closer to Neil Armstrong than to the pyramid builders.

Is Oxford University older than the Aztec Empire?

Yes. Teaching at Oxford is documented from 1096 and grew quickly after 1167. The Aztec Empire, the Triple Alliance of Tenochtitlan, Texcoco and Tlacopan, was formed in 1428. Oxford had been teaching for over 300 years when the Aztec Empire began, and the Empire lasted less than a century before the Spanish conquest of 1521.

Were woolly mammoths alive when the pyramids were built?

Yes. An isolated population of woolly mammoths survived on Wrangel Island in the Siberian Arctic until about 4,000 years ago, roughly 2000 BC. The Great Pyramid of Giza was finished around 2560 BC, some 500 years earlier. A 2024 genome study found the Wrangel population was stable for 6,000 years and then collapsed suddenly, for reasons still unknown.

How old is writing?

The oldest writing systems appear around 3400 to 3200 BC in Mesopotamia (cuneiform) and Egypt (hieroglyphs). Writing was invented independently at least three or four times: there, in China around 1250 BC, and in Mesoamerica by about 900 to 600 BC. Modern humans have existed for roughly 300,000 years, so written records cover under 2% of our history.

How much of an atom is empty space?

Atoms are almost entirely empty space. A hydrogen atom is about 100,000 times wider than its nucleus; scale the nucleus up to a football and the electron would be several kilometres away. Compress all 8 billion humans to nuclear density and they would occupy about 2 cubic centimetres, the size of a sugar cube.

How far away is the Voyager 1 spacecraft?

In October 2026 Voyager 1 is about 25.7 billion km from Earth, roughly 172 times the Earth-Sun distance. A radio signal takes nearly 24 hours to reach it; on 18 November 2026 it passes one full light-day away. Launched in 1977, it is the most distant human-made object and still returns data from a handful of instruments.

How much plastic has humanity produced in total?

Humanity had made about 8.3 billion tonnes of plastic by 2015, and production has run above 400 million tonnes a year since, so the total now exceeds 10 billion tonnes. Of all plastic waste ever generated, roughly 9% has been recycled, 12% incinerated and the rest landfilled or lost to the environment. Half of all plastic ever made was produced after 2004.

How fast are forests disappearing?

The world lost about 10.9 million hectares of forest a year to deforestation in 2015 to 2025, down from 17.6 million a year in the 1990s. Regrowth offsets part of it, for a net loss of about 4.1 million hectares a year, roughly the area of Switzerland. Total forest area has fallen about 4% since 1990.

What percentage of the world uses the internet?

About 5.5 billion people, 68% of the world, used the internet in 2024, up from about 7% in 2000 and 53% in 2019. Roughly 2.6 billion people remain offline, most of them in low-income countries and rural areas. Europe and North America are above 90% penetration; Africa is below 40%.

What percentage of the world owns a smartphone?

About 5.8 billion people, 70% of the world, use a mobile phone (early 2025), and smartphones make up roughly 87% of handsets in use. That puts smartphone users at around 5 billion, or 60% of humanity. In high-income countries ownership is above 90%; growth now comes mostly from South Asia and Africa.

What percentage of people live in cities?

By national definitions about 58% of people lived in urban areas in 2025, up from 30% in 1950. The UN's new harmonised method (2025) splits the world differently: 45% in cities, 36% in towns, 19% rural. There are 33 cities with over 10 million people; Jakarta, Dhaka and Tokyo are the largest under the new definition.

What percentage of food calories are wasted globally?

About 19% of food available to consumers, around 1.05 billion tonnes, was wasted in 2022 at households, food service and retail, with another 13% lost between harvest and shop. Households account for 60% of the waste. Food loss and waste produce an estimated 8 to 10% of global greenhouse gas emissions.

What is the average upper hearing limit for adults?

Young adults with healthy ears hear up to about 20 kHz, but the upper limit falls with age. Studies of extended high-frequency hearing find most people in their 30s and 40s top out around 15 to 17 kHz, and by the 50s many cannot hear above 12 to 14 kHz. The loss starts at the highest frequencies and creeps downward as hair cells at the base of the cochlea wear out.

How many people have hearing loss?

Over 1.5 billion people, about 20% of the world, have some degree of hearing loss, and about 430 million have loss severe enough to need rehabilitation. WHO projects that by 2050 nearly 2.5 billion people will have some hearing loss and 700 million will need care. Over a billion young people are at risk from loud recreational sound.

At what volume does hearing damage begin?

Occupational guidelines treat 85 decibels averaged over an 8-hour day as the exposure limit, and each 3 dB increase halves the safe time. Normal conversation is about 60 dB; a concert runs 100 to 110 dB, where safe exposure is measured in minutes. WHO estimates over 1 billion young people risk hearing loss from loud headphones and venues.

What is the 'Mosquito tone' used to deter teenagers?

The Mosquito is a device that emits a 17.4 kHz tone, which most people over about 25 cannot hear because high-frequency sensitivity declines with age. It went on sale in 2005 to disperse loitering teenagers and drew complaints as discriminatory. Teenagers soon turned the idea around, using the tone as a ringtone their teachers could not hear.

How many items can the human brain hold in working memory?

George Miller's 1956 paper noted that people hold about 7 (plus or minus 2) items in immediate memory. Later work by Nelson Cowan found that when rehearsal and chunking are blocked, the real capacity is closer to 4 items. Miller himself treated the number partly as a joke about coincidences; it became one of the most cited claims in psychology anyway.

How strongly does working memory predict IQ?

Working memory capacity correlates with fluid intelligence at roughly r = 0.5 to 0.7 when measured with several tasks, one of the strongest links in cognitive psychology. The two are not the same thing: a 2005 meta-analysis put the correlation closer to 0.5 and argued against treating them as identical. Working memory also predicts school achievement independently of IQ.

At what age does working memory peak?

Working memory performance peaks in the twenties and declines slowly afterwards. Simple digit span holds up well into the 60s, dropping by only about one item on average between ages 20 and 70. Tasks that require juggling or reordering information decline earlier and faster, and processing speed begins its slide in the 30s.

What is the average resting heart rate?

A normal adult resting heart rate is 60 to 100 beats per minute. The population average sits around 70 bpm, with women averaging a few beats higher than men. Endurance athletes often rest at 40 to 60 bpm because a trained heart pumps more blood per beat. Resting heart rate is a simple fitness marker that costs nothing to measure.

How does resting heart rate affect longevity?

In a 16-year follow-up of 2,798 Danish men, those with a resting heart rate above 90 bpm had about three times the mortality of men below 50 bpm, after adjusting for fitness. A 2016 meta-analysis of 46 cohort studies found each extra 10 bpm at rest came with about 9% higher all-cause mortality. These are associations, and fitness explains part of them.

What heart rate do elite athletes have?

Elite endurance athletes commonly have resting heart rates of 40 to 50 bpm. Cyclist Miguel Indurain was reported to have a resting rate of 28 bpm, among the lowest recorded in a healthy adult. The athlete's heart has a larger left ventricle and ejects more blood per beat, so it needs fewer beats at rest.

What is the maximum heart rate during exercise?

The classic rule of thumb for maximum heart rate is 220 minus age, which gives 190 bpm at 30. It was never derived from a proper study and is off by 10 bpm or more for many people. A 2001 meta-analysis fitted 208 minus 0.7 times age instead. Training zones are usually set at 50 to 70% of maximum for moderate effort and 70 to 85% for vigorous.

What percentage of people are introverted?

Introversion is a continuum, so the share depends on where you draw the line. On Big Five extraversion scales, scores are roughly bell-shaped with most people near the middle; about one in six score more than one standard deviation below the mean, a reasonable definition of strongly introverted. The popular 'half of people are introverts' line comes from Myers-Briggs type data, which forces a binary split.

Is introversion genetic?

Twin studies put the heritability of extraversion-introversion at roughly 40 to 60%, among the highest for personality traits. Most of the remaining variance is 'non-shared environment', the experiences that differ even between siblings in the same home; shared family environment contributes little. Identical twins raised apart score far more alike than fraternal twins.

Which countries are the most introverted?

Cross-cultural Big Five studies find East Asian samples (Japan, South Korea, China) and some Northern European samples score lower on extraversion, while samples from the United States, Australia and parts of Latin America score higher. Differences between countries are small compared with differences within them, and translation and response style account for part of the gap.

Do introverts have physically different brains?

Some differences have been reported, but the evidence is thin. A 2012 MRI study of 32 men found introverts had more grey matter in parts of the right prefrontal cortex and temporo-parietal junction, regions tied to inhibition and introspection. A 1999 PET study found higher blood flow in frontal regions in introverts. Samples are small, and a 2025 review found no consistent anatomical map of extraversion.

Do men and women have different risk tolerances?

Across cultures and domains, men on average report and display more risk tolerance than women, with a gap of around 0.2 to 0.4 standard deviations. In the Global Preferences Survey covering 76 countries, women were less risk-tolerant in nearly every country. The gap is larger for physical and financial risk than for social risk, and it shrinks when wealth and knowledge are held equal.

How does risk tolerance change with age?

Self-reported risk tolerance falls steadily across adulthood. In a German panel of over 40,000 people it declined almost linearly from the 20s to the 60s and then levelled off, after netting out period effects. The drop is sharpest for physical risk. Tolerance for social and career risk holds up better with age.

Which countries have the highest risk tolerance?

The Global Preferences Survey (80,000 people, 76 countries) found self-reported risk tolerance highest in parts of Africa and the Middle East and lowest in parts of Europe and East Asia; richer countries were not systematically more risk-tolerant. Within countries, risk tolerance rises with income and education and falls with age. The measure combines survey questions with incentivised lottery choices.

How many hairs does the average person have on their head?

The average scalp carries roughly 100,000 hair follicles. Natural blondes tend to have more (about 150,000) and redheads fewer (about 90,000). People shed 50 to 100 hairs a day. Scalp hair grows about 1 cm a month, and each hair lives 2 to 7 years before it falls out and the follicle starts again.

How much blood is in the human body?

An average adult has about 5 litres of blood, roughly 7% of body weight, so a 70 kg person carries about 4.9 litres. Women average a little less than men. At rest the heart pushes the whole volume round about once a minute; during hard exercise, cardiac output can rise fivefold.

How fast do fingernails grow?

Fingernails grow about 3.5 mm a month and toenails about 1.6 mm, based on measurements in healthy adults. Growth slows with age and in cold weather and is slightly faster in the dominant hand. A fingernail takes around 6 months to replace itself fully; a big toenail, 12 to 18 months.

How fast is a sneeze?

Measured sneezes are slower than legend says. High-speed imaging found peak exhalation speeds around 4.5 m/s (about 16 km/h), far below the '160 km/h' figure that circulates online. The cloud of droplets can still travel several metres, up to about 8 m for the smallest droplets, which is why sneezes spread infections so well.

How many dreams does the average person have per night?

People typically have 3 to 5 dream periods a night, mostly during REM sleep, which recurs about every 90 minutes and lengthens toward morning. Most dreams are forgotten within minutes of waking. When woken from REM, people report a dream about 80% of the time; from deep non-REM sleep, far less often.

Has human attention span really dropped below a goldfish's?

No. The claim that attention spans fell from 12 seconds in 2000 to 8 seconds, below a goldfish's 9, comes from a 2015 Microsoft Canada marketing report that cited no study for those numbers. BBC's More or Less traced the figures and found no source. Goldfish, for the record, can be trained and remember for months. Attention varies with task and motivation, and there is no evidence of a species-wide decline.

How fast do signals travel through the brain?

Nerve signals travel at speeds that depend on the fibre. Thin, unmyelinated fibres carry pain and temperature signals at 0.5 to 2 m/s; thick, myelinated motor and touch fibres run at up to about 120 m/s (430 km/h). That is why a stubbed toe hurts twice: a sharp first pain arrives quickly on fast fibres, and a dull ache follows on the slow ones.

How old is the universe compared to Earth?

The universe is about 13.8 billion years old. Earth formed about 4.54 billion years ago, so it has existed for about a third of cosmic time. The first stars lit up within a few hundred million years of the Big Bang. The earliest fossil evidence of life on Earth dates to about 3.5 billion years ago; complex animals only appear about 600 million years ago.

How long ago did the dinosaurs go extinct?

Non-avian dinosaurs died out about 66 million years ago after the Chicxulub asteroid impact. Our species is roughly 300,000 years old, so the extinction is about 220 times further back than the origin of Homo sapiens. Birds descend from theropod dinosaurs, so dinosaurs in the strict sense are still here; the earliest known bird-like dinosaurs are about 150 million years old.

Can you see the Great Wall of China from space?

No. The wall is only 5 to 8 metres wide at the base and roughly matches the colour of the surrounding land, so the naked eye cannot pick it out from orbit. China's first astronaut, Yang Liwei, said in 2003 that he could not see it. From the International Space Station, with a camera and good light, it has been photographed, but so have motorways and airports, which are wider.

How many books existed before the printing press?

Before Gutenberg (about 1450), books were copied by hand, and total output across medieval Western Europe is estimated at roughly 10 million manuscripts over a thousand years. In the first 50 years of printing, about 20 million copies were produced; in the 16th century, 150 to 200 million. Google estimated about 130 million distinct book titles in 2010.

What is the most spoken language in the world?

Mandarin Chinese has the most native speakers at about 940 million. English has about 380 million native speakers but around 1.5 billion speakers in total once second-language users are counted, which makes it the most spoken language overall. Spanish (about 485 million native speakers) and Hindi follow.

How many countries are in the world?

The United Nations has 193 member states plus 2 observer states (the Holy See and Palestine), for a total of 195. Other lists add Taiwan, Kosovo and other partially recognised states and reach 197 or more. The UN started in 1945 with 51 members; the newest, South Sudan, joined in 2011.

What percentage of people own their home?

There is no clean global figure; survey coverage is patchy outside rich countries. In OECD countries, ownership ranges from over 90% of households in Romania to under 45% in Switzerland and Germany, where renting is the norm. The US rate is about 65%. Ownership has fallen for younger adults in most English-speaking countries since the 1990s.

How many steps does the average person take per day?

Smartphone data from 717,000 people in 111 countries found a global average of about 4,960 steps a day. Hong Kong led at 6,880; Indonesia was lowest at 3,513. The '10,000 steps' target began as a 1965 Japanese pedometer marketing campaign (the manpo-kei), not as a medical finding, and health benefits appear well below it.

How much of your life do you spend working?

A full-time career of 40 years at about 1,700 hours a year comes to roughly 70,000 to 90,000 working hours, around a third of waking adult life. Hours differ a lot by country: in 2024 the average US worker put in about 1,800 hours, a UK worker about 1,500, and a German worker about 1,340.

How many times does the average person laugh per day?

The often-quoted figures (adults 15 times a day, children 300) have no traceable study behind them; Robert Provine, who studied laughter for decades, said nobody has actually counted. What is well documented: laughter is about 30 times more frequent in company than alone, and most of it follows ordinary remarks rather than jokes.

Does the Amazon produce 20% of the world's oxygen?

No. The Amazon produces a lot of oxygen through photosynthesis, but its plants, animals and microbes consume nearly all of it through respiration and decay, so the net contribution to the atmosphere is close to zero. Atmospheric oxygen is a 20% stockpile that changes very slowly. Roughly half of the oxygen produced on Earth each year comes from marine phytoplankton.

What percentage of Earth's surface is covered by water?

About 71% of Earth's surface is covered by water, but 97% of that is salt water. Of the roughly 2.5% that is fresh, about 69% is locked in glaciers and ice caps and most of the rest is groundwater. Lakes and rivers hold only about 0.3% of fresh water, so readily accessible surface fresh water is around 0.01% of all water on Earth.

How many atoms are in the human body?

A 70 kg human body contains roughly 7 × 10²⁷ atoms. By count, about 62% are hydrogen, 24% oxygen and 12% carbon; by mass, oxygen dominates because of water. The atoms are not permanent: most are exchanged over years through eating, breathing and excretion, and the heavier elements were made in stars before the Sun formed.