I was a bit skeptic about your comment and Jaruzel's one until I saw this chart: https://en.wikipedia.org/wiki/World_population#/media/File:Population-doubling.

I was a bit skeptic about your comment and Jaruzel's one until I saw this chart: https://en.wikipedia.org/wiki/World_population#/media/File:Population-doubling.svg https://en.wikipedia.org/wiki/World_population#/media/File:P... Population is doubled every 2 generations during the 20th century. If nothing else changed, the probability of human advancement should have been at least 2x. There are other factors like better life expectation that speed up advancement a lot (more probabilty of having advancement per generation). But I think the literacy factor is the key. Sadly I have no data to prove it, but I bet this was the cause of all this.