> So for the majority of human existence 1/3 to 1/2 died before their 5th birthday
Correction: 1/3 to 2/3, early 18th century london had an infant mortality rate of 745/1000.
> Same story in classical rome or medieval England, LEB in the high 20s but once an initial gap passed, effective life expectancy grew to 50~60 (total)
Addition: an english peer (aristocrat) of the late middle-ages (15th~16th century) having reached 21 had a total life expectancy of ~70, LEB for peers was in the low 30s.
Essentially, for most of human history life expectancy was highly bimodal, a large part of the population would die extremely early, and most of the rest would make it to (what is now qualified as) middle to late adulthood.
Correction: 1/3 to 2/3, early 18th century london had an infant mortality rate of 745/1000.
> Same story in classical rome or medieval England, LEB in the high 20s but once an initial gap passed, effective life expectancy grew to 50~60 (total)
Addition: an english peer (aristocrat) of the late middle-ages (15th~16th century) having reached 21 had a total life expectancy of ~70, LEB for peers was in the low 30s.
Essentially, for most of human history life expectancy was highly bimodal, a large part of the population would die extremely early, and most of the rest would make it to (what is now qualified as) middle to late adulthood.