try the world(google), it's actually closer to finland

Yes, because much of the world export our slave-like labour to poor regions of the world. Those poor people clearly need to be counted in our life expectancy if we are to compare to a time when slaves where in the household etc. Export of misery does make the numbers look nice though.

Africa does not have a 50% child mortality rate. What it has is an an average of 5 children born per woman. In short: not even the worst place in Africa today is as bad as the best place any time before 1900.