A rather crude (and perhaps incorrect) conclusion could be. Some of these countries aleady decided to make sure their offspring populated the lands early on. And other started to do that now. Plus Industries have changed, no more "one of the first and only" of a lot of things
I was thinking, man i still miss THREE in the
2000 one ! What could they be. And why am i missing more in the 2000 one than in any of the others...
And the changes after 1900 are crazy! Up until then all the countries seem to grow at a reasonably steady pace. Graphs will have gone like __/
Sorry for being cynical. But well.. I dunno society is weird, I am weird, whatcha gonna do..