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.

In 1870, the average person born in Colombia could expect to live to the age of 32 years old, a figure which would see only marginal increase in the country until the 1930s (with a minor decline in 1920 from the 1918 Spanish Flu epidemic). However, life expectancy would begin to increase rapidly starting in the 1930s, as a series of reforms and modernization programs following the Great Depression, combined with a relatively quick recovery from the financial crisis, would see significant improvements in standards of living and access to healthcare in the country. As a result, life expectancy would increase by nearly twenty years between 1930 and 1950 alone, and this would continue at an accelerated rate through much of the remainder of the century. While the economic and political instability resulting from the increased drug cartel and government clashes of the 1990s would see a pause in life expectancy growth, increases have largely resumed in the 21st century, and in 2020, it is estimated that the average person born in Columbia can expect to live to just over 77 years old.

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 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.

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.

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.

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 1800, the average child born in the region of present-day Turkey was expect to live to the age of 35. This figure would see little change for most of the 19th century, rising to just 36 years by the beginning of the 20th century. However, Turkey’s life expectancy would fall greatly with the beginning of the First World War in 1914, as both extensive wartime casualties and an organized campaign of mass execution and deportation of the Ottoman Empire's non-Turkish populations would result in the deaths of approximately three million people; the victims of the respective Armenian, Assyrian and Greek genocides are thought to make up over half of these deaths.

Following the collapse of the Ottoman Empire and establishment of the Turkish Republic in 1923, life expectancy in Turkey would begin to recover somewhat, but would proceed to fall again in the late 1930s, as the Great Depression and the Second World War would cause significant economic harm to the country, despite Turkey’s neutrality for much of the conflict. However, the 1950s would see Turkey’s population begin to grow rapidly, as the republic would begin to rapidly modernize both the country’s healthcare and economy, and mass immunization programs would lead to a sharp drop in child mortality. As a result, Turkey’s life expectancy would rise to over 68 years by 2000, with a slight increase beginning in the early 2000s after healthcare reforms in the country established universal healthcare in the country. As a result, in 2020, it is estimated that the average person born in Turkey will live to an age of just over 77 years.

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.

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 Finland was 35.3 in the year 1765, and over the course of the next 255 years, it is expected to have increased by over double this, to 81.6 years by 2020. Although life expectancy has generally increased throughout Finland's history, it fluctuated greatly between 1765 and 1875, in the 1910s because of the Spanish Flu epidemic that swept across the world and the Finnish Civil War, and again during the Second World War in the 1930s and 40s.

In 1870, the average life expectancy in South Africa was 33.5 years from birth. This life expectancy would remain largely unchanged until the late-1910s, where life expectancy would drop to as low as thirty years as a result of the 1918 Spanish Flu epidemic. In the 1930s, life expectancy in South Africa would begin to steadily rise, peaking at over 63 years in 1995, as industrialization and greater access to healthcare and vaccinations led to significantly reduced child mortality rates across the region. However, life expectancy experienced a sudden drop beginning after 1995, as the HIV/AIDS epidemic spread throughout the country, beginning in the early 1990s. As the epidemic spread through the country, life expectancy would fall by almost 10 years, bottoming out below 54 years in 2005. Life expectancy would begin to rise again beginning in the early 2010s however, as access to HIV counselling and treatments, such as antiretroviral therapy, became more widely available throughout the region. Life expectancy in the country is estimated to be almost 64 years from birth in 2020; a return to the pre-HIV figures of the early 1990s.

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.

In the century between 1920 and 2020, life expectancy more than doubled in Albania, increasing from approximately 32 years in 1920, to 78 years in 2020. Between 1925 and 1930, life expectancy stagnated, due to political instability and poor economic opportunities, although it then increased well into the late 1930s. It was during the Second World War when life expectancy decreased, as Albania was annexed first by Italy, and later by Germany. An estimated 30,000 Albanians perished as a direct result of the war, and life expectancy fell by almost three years in this five year period. In the 1950s, Albania's pre-war trajectory continued, and life expectancy rose to above 50 years in 1950, and has gradually increased to over 78 years today. There was a slight decrease in life expectancy in the early 1990s, as the communist system in Eastern Europe collapsed, however Albania's life expectancy has since increased well above the global average.

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.

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 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.

Life expectancy in Norway was 35 years in 1765, and over the course of the next 255 years, it is expected to have increased to 82.2 years by 2020. Although life expectancy has generally increased throughout history, there were several times where the rate deviated from its previous trajectory. These changes were a result of famine and influenza epidemics between 1765 and 1865, and again in the 1910s because of the Spanish Flu epidemic that spread across Europe.

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.

In 1910, life expectancy from birth in the region of present-day Syria was estimated at 32 years. This figure would see little change until 1935, outside of a brief dip in the late 1910s as the 1918 Spanish Flu epidemic would spread across the area. Life expectancy then began rising sharply from the late 1930s onwards, as modernization programs implemented by French, British and, later, independent authorities saw mass vaccination campaigns and healthcare improvements which greatly reduced child mortality rates. This climb would continue throughout the rest of the 20th century, and as a result, by 2000, the average person born in Syria could expect to live to over the age of 72.

However, life expectancy would see a sudden fall with the beginning of the Syrian Civil War in 2011. After peaking at just over 74 years in 2010, life expectancy would fall to just under 70 years by 2015, as the country’s civil war would lead to an estimated half a million fatalities, as well as mass displacement and the exodus of refugees from the country. As the fighting has gradually decreased in intensity in recent years, life expectancy of Syria has risen slightly, and in 2020, the average person born in Syria can expect to live to just over 71 years on average; although there is a difference of over eleven years in life expectancy between male and females.