What this chart shows:
Every time I talk about the increase of life expectancy there is at least one person who claims that this is not very meaningful as this statistic “is skewed” by the decrease in child mortality. Yes, child mortality matters a lot – but there is more to the increase in life expectancy than this. This chart shows it!
Before the onset of modernity – with the advancements in science and the increase of living standards – life was short. As we have seen in the1st chart in this series, in 1800 there was no country in the world where the life expectancy was higher than 40 years.
The gains in life expectancy since then were mostly due to changing mortality patterns at a young age: It was common that every 3rd or even 2nd child died, and it has dropped dramatically since then. See the data entry on child mortality on OurWorldInData.
But this chart here shows that the increase of life expectancy was by far not entirely due to the decrease in child mortality: Child mortality is defined as the number of children dying before their 5th birthday. To see how life expectancy has improved without taking child mortality into account we therefore have to look at the prospects of a child who just survived their 5th birthday: In 1845 a 5-year old had a expectancy to live 55 years. Today a 5-year old can expect to live 82 years. An increase of 27 years!
And also at higher ages mortality patterns have changed. A 50-year old could expect do live twenty more years. Today the life expectancy of a 50-year old is 83!
And another important change can be studied in this chart: Health inequality decreased hugely! Look by how much life expectancy differed by age in 1845 – from 40 years for newborns to 79 for 70-year olds. Today this span is much smaller – from 81 to 86. This is because the chance of dying at a younger age has been steadily decreasing, which means that the equality of life spans has increased.
The data for life expectancy by age is taken from the Human Mortality Database. University of California, Berkeley (USA), and Max Planck Institute for Demographic Research (Germany). Available at www.mortality.org (data downloaded on 11 February 2014 – being granted permission to use this data for the visualisation on 13 February 2014).
The data on life expectancy at birth before 1845 is taken the data from Kertzer and Laslett (eds) (1995) – Aging in the Past: Demography, Society, and Old Age. Berkeley: University of California Press. Online here. Their sources are the ‘British official statistics’ and Wrigley and Schofield  1989.
(The Human Mortality Database data refers to remaining life expectancy for people in a 5 year age bracket (10-14, 15-19, …). To calculate total life expectancy I have added the lower bound of each range to the remaining life expectancy for the given age group – the values here should therefore be understood as the lower bound for total life expectancy.)
Link to OurWorldInData.org
The interactive version of this chart – showing the life expectancy by 5-year interval up to the age of 110 – is available in the data entry on life expectancy.