[anonym29]

https://www.statista.com/statistics/1040079/life-expectancy-...

Note that LEAB of 60 does not imply that fewer than 1% live beyond 65, nor does a payer:payee ratio above 100.

For most of human history, deaths followed a largely bimodal distribution - high infant mortality, lower morality in mid life, and then high mortality (approaching 100%) in old age. Put more simply: if you lived to, say, 3, you were much more likely than a newborn to make it to 70. A large enough portion didn't make it past infancy that it dragged down the entire average.

Much of the improvement in LEAB has been from improvements in infant mortality, not people living longer at the end of their lives (though that is increasingly a factor as medical care is improving).

Part of the discrepancy of the payer:payee ratio was due to more people having more kids, and a big part of that change is explained by our switch from a regular population distribution (many more young people than old people) to an inverted pyramid population distribution, like Japan's (a larger cohort of old people, increasingly smaller cohorts of younger people).