Comment by saalweachter

The stat I keep in my back pocket is that you can roughly divide the total time lived by humans (the integral of population over time) into three tranches, with one third of human experience being before the dawn of agriculture, and one third being after 1600. (Related fun fact: WWII was about 1% of human experience, based on the back of the envelope that ~50% of the world experienced "being at war" for nearly a decade.)

The distribution of human lives versus years lived by humans will skew earlier, because infant mortality was absurd for the first two tranches, with something like 50% of people dying before the age of five, so it will be more like 40-40-20 over those time periods.