In hunter-gatherer, pre-agricultural times, the human life expectancy was about 20 to 30 years. That’s also what it was in Western Europe in Late Roman and in Medieval times. It didn’t rise to 40 years until around the year 1870. It reached 50 in 1915, 60 in 1930, 70 in 1955, and is today approaching 80 (a little more for women, a little less for men).
