Over the past 160 years, life expectancy (from birth) in the United States has risen from 39.4 years in 1860, to 78.9 years in 2020. One of the major reasons for the overall increase of life expectancy in the last two centuries is the fact that the infant and child mortality rates have decreased by so much during this time. Medical advancements, fewer wars and improved living standards also mean that people are living longer than they did in previous centuries.

Despite this overall increase, the life expectancy dropped three times since 1860; from 1865 to 1870 during the American Civil War, from 1915 to 1920 during the First World War and following Spanish Flu epidemic, and it has dropped again between 2015 and now. The reason for the most recent drop in life expectancy is not a result of any specific event, but has been attributed to negative societal trends, such as unbalanced diets and sedentary lifestyles, high medical costs, and increasing rates of suicide and drug use.

A global phenomenon, known as the demographic transition, has seen life expectancy from birth increase rapidly over the past two centuries. In pre-industrial societies, the average life expectancy was around 24 years, and it is believed that this was the case throughout most of history, and in all regions. The demographic transition then began in the industrial societies of Europe, North America, and the West Pacific around the turn of the 19th century, and life expectancy rose accordingly. Latin America was the next region to follow, before Africa and most Asian populations saw their life expectancy rise throughout the 20th century.

Life expectancy in the United Kingdom was below 39 years in the year 1765, and over the course of the next two and a half centuries, it is expected to have increased by more than double, to 81.1 by the year 2020. Although life expectancy has generally increased throughout the UK's history, there were several times where the rate deviated from its previous trajectory. These changes were the result of smallpox epidemics in the late eighteenth and early nineteenth centuries, new sanitary and medical advancements throughout time (such as compulsory vaccination), and the First world War and Spanish Flu epidemic in the 1910s.

Life expectancy in Germany was below 39 in the year 1875, and over the course of the next 145 years, it is expected to have increased to above 81 years in the year 2020. Although life expectancy has generally increased throughout Germany's history, there were several times where the rate deviated from its previous trajectory. The most notable changes were because of the First and Second World Wars, in the first half of the twentieth century.

Life expectancy in India was 25.4 in the year 1800, and over the course of the next 220 years, it has increased to almost 70. Between 1800 and 1920, life expectancy in India remained in the mid to low twenties, with the largest declines coming in the 1870s and 1910s; this was because of the Great Famine of 1876-1878, and the Spanish Flu Pandemic of 1918-1919, both of which were responsible for the deaths of up to six and seventeen million Indians respectively; as well as the presence of other endemic diseases in the region, such as smallpox. From 1920 onwards, India's life expectancy has consistently increased, but it is still below the global average.

In 1875, those born in the present-day region of Indonesia lived to an averae age of thirty years. This figure would remain largely stagnant until the 1910s, where the the 1918 Spanish Flu epidemic would cause life expectancy to fall to just 27 years as the epidemic spread across the region. Following the end of the Spanish Flu epidemic in 1920, life expectancy would begin to rise in Indonesia, as public works and infrastructure programs by the Dutch colonial administration would see standards of living begin to rise in the country. However, after peaking at 36 years in 1940, life expectancy would fall to just thirty years once more with the invasion and subsequent occupation of the island by the Empire of Japan in 1942; most estimates suggest that between 2.4 and four million people in Indonesia died from famine, forced labor and violence during the Second World War.

Life expectancy would begin rising following the country’s independence from the Dutch in 1949, particularly in the early 1950s as mass immunization and vaccination, combined with rapid modernization would see child mortality and standards of living rise throughout the remainder of the century, reaching over 65 years by the turn of the millennium. This rise in life expectancy has continued in the 21st century, and in 2020, the average person born in Indonesia is expect to live to beyond the age of 71 years.

Life expectancy in Japan was 36.4 in the year 1860, and over the course of the next 160 years, it is expected to have increased to 84.4, which is the second highest in the world (after Monaco). Although life expectancy has generally increased throughout Japan's history, there were several times where the rate deviated from its previous trajectory. These changes were a result of the Spanish Flu in the 1910s, the Second World War in the 1940s, and the sharp increase was due to the high rate of industrialization and economic prosperity in Japan, in the mid-twentieth century.

In 1870, the average person born in Ecuador could expect to live to just under the age of 33. Outside of a temporary drop in the late 1910s, the result of the 1918 Spanish Flu epidemic, life expectancy in Ecuador would see only modest growth for much of the first half of the 20th century, reaching just over 35 years in 1940. However, life expectancy would begin to rise sharply in the 1940s, as reforms under President Galo Plaza Lasso would bring a period of stability and economic growth to the country, greatly improving standards of living and seeing the infant mortality rate drop dramatically. Between 1940 and 1950 alone, life expectancy would jump by more than twelve years, to almost 48 years.

Following the end of Galo Plaza’s term in 1952, Ecuador would endure a period of instability and civil unrest, causing life expectancy to temporarily stagnate for several years. However, life expectancy would begin to grow rapidly again starting in the 1960s as modernization would see a continuation of the improvements made in the 1940s. This growth would continue steadily into the 21st century, and in 2020, life expectancy from birth is almost 77 years.

Life expectancy in Poland was 35.9 in the year 1885, and over the course of the next 135 years, it is expected to have increased to 78.5 by the year 2020. Although life expectancy has generally increased throughout Poland's history, the most noticeable decline came in the 1940s as a result of the Second World War and Holocaust, which caused Poland's population to decline by about 17 percent, which was more than any other country.

Life expectancy in China was just 32 in the year 1850, and over the course of the next 170 years, it is expected to more than double to 76.6 years in 2020. Between 1850 and 1950, finding reliable data proved difficult for anthropologists, however some events, such as the Taiping Rebellion and Dungan Revolt in the nineteenth century did reduce life expectancy by a few years, and also the Chinese Civil War and Second World War in the first half of the twentieth century. In the second half of the 1900s, Chinese life expectancy increased greatly, as the country became more industrialized and the standard of living increased.

In 1870, Brazil's life expectancy from birth was just 32 years; there was a slight increase over the next 65 years, with the only decrease coming in the 1910s during the Spanish Flu epidemic. The largest increases in life expectancy came in the 1940s, when it jumped by almost twelve years in this decade alone. Brazil's life expectancy from birth has increased steadily over the past fifty years, and life expectancy in 2020 is almost 76; more than double what it was in 1940.

Life expectancy in France was below thirty in the late 1700s, but over the course of the next two and a half centuries it is expected to reach 82.5 by the year 2020. Although life expectancy has generally increased throughout France's history, there were several times where the rate deviated from its previous trajectory. The most noticeable changes were because of smallpox and influenza epidemics in the 1700s, medical advancements (such as vaccination and pasteurization) saw life expectancy increase in the 1800s, and then both World Wars and the epidemics that followed caused brief drops in the first half of the twentieth century.

At the beginning of the 1840s, life expectancy from birth in Ireland was just over 38 years. However, this figure would see a dramatic decline with the beginning of the Great Famine in 1845, and dropped below 21 years in the second half of the decade (in 1849 alone, life expectancy fell to just 14 years). The famine came as a result of a Europe-wide potato blight, which had a disproportionally devastating impact on the Irish population due to the dependency on potatoes (particularly in the south and east), and the prevalence of a single variety of potato on the island that allowed the blight to spread faster than in other areas of Europe. Additionally, authorities forcefully redirected much of the country's surplus grain to the British mainland, which exacerbated the situation. Within five years, mass starvation would contribute to the deaths of over one million people on the island, while a further one million would emigrate; this also created a legacy of emigration from Ireland, which saw the population continue to fall until the mid-1900s, and the total population of the island is still well below its pre-famine level of 8.5 million people.

Following the end of the Great Famine, life expectancy would begin to gradually increase in Ireland, as post-famine reforms would see improvements in the living standards of the country’s peasantry, most notably the Land Wars, a largely successful series of strikes, boycotts and protests aimed at reform of the country's agricultural land distribution, which began in the 1870s and lasted into the 20th century. As these reforms were implemented, life expectancy in Ireland would rise to more than fifty years by the turn of the century. While this rise would slow somewhat in the 1910s, due to the large number of Irish soldiers who fought in the First World War and the Spanish Flu pandemic, as well as the period of civil unrest leading up to the island's partition in 1921, life expectancy in Ireland would rise greatly in the 20th century. In the second half of the 20th century, Ireland's healthcare system and living standards developed similarly to the rest of Western Europe, and today, it is often ranks among the top countries globally in terms of human development, GDP and quality of healthcare. With these developments, the increase in life expectancy from birth in Ireland was relatively constant in the first century of independence, and in 2020 is estimated to be 82 years.

In 1870, life expectancy from birth in the modern-day territory of Iran was approximately 25.6 years. This figure would see little change in Iran for much of the late 19th and early 20th century; the only major change was the dip in the late 1910s, resulting from the 1918 Spanish Flu epidemic) and a famine from 1918 to 1919, which led to significant fatalities across the region. Life expectancy would begin to grow rapidly in the 1940s, as the country’s oil reserves, discovered in 1908, would see an economic boom in the years during and immediately following the Second World War, providing a valuable source of funding for socio-economic reforms implemented under Reza Shah. This, in turn, saw a rapid modernization of healthcare in the country, as well as the implementation of mass vaccination programs in the early 1940s, which greatly lowered child mortality rates and allowed life expectancy to rise.

As implementation of these programs would continue, life expectancy from birth rose from just over 27 years in 1940, to approximately 39 years in 1950. After the end of the rapid growth of the 1940s, life expectancy would continue steadily rise until 1980, peaking at 56.7 years. However, life expectancy would fall to just 52 years in 1985, the result of mass fatalities in the Iran-Iraq War of 1980 to 1988. Following the war’s end with a UN-brokered ceasefire in 1988, life expectancy would quickly recover, reaching over 69 years by the turn of the century. Life expectancy has continued to rise throughout the 21st century, and it is now estimated that the average child born in Iran in 2020 will live to the age of approximately 76 years.

Life expectancy in Spain was below thirty in the year 1880, and over the course of the next 140 years, it is expected to have increased to 83.4 by the year 2020. Although life expectancy has generally increased throughout Spain's history, there were several times where the rate deviated from its previous trajectory. The most notable changes were a result of the global influenza epidemic of the 1910s, (called the 'Spanish Flu' as it received more press coverage in neutral Spain, during the First World War) and the Spanish Civil War two decades later.

Life expectancy in Russia was 29.6 in the year 1845, and over the course of the next 175 years, it is expected to have increased to 72.3 years by 2020. Generally speaking, Russian life expectancy has increased over this 175 year period, however events such as the World Wars, Russian Revolution and a series of famines caused fluctuations before the mid-twentieth century, where the rate fluctuated sporadically. Between 1945 and 1950, Russian life expectancy more than doubled in this five year period, and it then proceeded to increase until the 1970s, when it then began to fall again. Between 1970 and 2005, the number fell from 68.5 to 65, before it then grew again in more recent years.

Life expectancy in Italy was just under thirty in the year 1870, and over the course of the next 150 years, it is expected to have increased to 83.3 by the year 2020. Although life expectancy has generally increased throughout Italy's history, there were several times where the rate deviated from its previous trajectory. The most noticeable changes were a result of the First World War and Spanish Flu epidemic, and also the Second World War and Italian Civil War.

The life expectancy for men aged 65 years in the U.S. has gradually increased since the 1960s. Now men in the United States aged 65 can expect to live 17 more years on average. Women aged 65 years can expect to live around 19.7 more years on average.

Life expectancy in the U.S.

As of 2021, the average life expectancy at birth in the United States was 76.33 years. Life expectancy in the U.S. had steadily increased for many years but has recently dropped slightly. Women consistently have a higher life expectancy than men but have also seen a slight decrease. As of 2019, a woman in the U.S. could be expected to live up to 79.3 years.

Leading causes of death

The leading causes of death in the United States include heart disease, cancer, unintentional injuries, chronic lower respiratory diseases and cerebrovascular diseases. However, heart disease and cancer account for around 38 percent of all deaths. Although heart disease and cancer are the leading causes of death for both men and women, there are slight variations in the leading causes of death. For example, unintentional injury and suicide account for a larger portion of deaths among men than they do among women.

In 1880, the average person born in the area of modern-day South Korea could expect to live to just under the age of 26, a figure which would remain below thirty until the 1920s. Life expectancy would fall to its lowest level of just 24 years in 1920, however, as the 1918 Spanish Flu epidemic would spread through the country, resulting in an estimated 200,000 deaths across the Korean peninsula. Life expectancy would begin to rise in the 1920s, however, as development programs by the Japanese colonial administration would see economic growth and access to healthcare improve greatly in the region. The 1940s and 1950s would see a slowing, then a reversal to this growth though, as the final years of the Second World War, and later the 1950 Korean War, would see significant destruction and fatalities in the country.

Following the end of the Korean War with the 1953 armistice, life expectancy would begin to climb again in the newly-established South Korea, as the country would begin to rapidly modernize and improve access to healthcare and nutrition, raising standards of living and cutting child mortality rates throughout the country. As a result, life expectancy would rise from just under 47 years in 1950, to over 75 years by the turn of the century. This rise in life expectancy has continued steadily into the 21st century, and as a result, in 2020, it is estimated that the average person born in South Korea will live to just under the age of 83 years, one of the highest life expectancies in the world.

Life expectancy in Portugal was 35.6 years in 1915, and over the course of the next century, it is expected to have increased by more than double, to 81.8 in 2020. Although life expectancy has generally increased throughout Portugal's history, there was a decline in the 1910s, as a result of the worldwide influenza pandemic, that is now known as the Spanish Flu. From this point onwards, Portugal's life expectancy increased at every five year interval.