Have you ever wondered how many human beings have ever lived on earth? Go on take a guess. And what percentage of those people are alive today?
This page on the
Population Reference Bureau website
does it's best to make a sound estimate and explains the rationale in some detail.
It surprises me just how small the total is and how high the percentage that are alive today.
One sobering fact is that "Life expectancy at birth probably averaged only about 10 years for most of human history." So much for the "good old days".