Put another way:

It's falling in Western countries because we're commiting cultural suicide for the reasons I cited for Europe (the US is behind Europe, but seems to be on the same road). It's falling in countries like China because they moved like 70% of their population from farms to huge cities in the last 40 years, which causes their society to work much more like... the West. Places like Africa, etc. are falling as they get more access to birth control, work for women, etc.

I guess I should have said this: I theorize that the whole world is following a similar path, but different areas started sooner and are thus much farther along in their decadence. Africa is now where the US was in 1965. Europe today may be what the US looks like in 20 years.

Obviously though Western cultural beliefs are much easier to spread now than they were decades ago, so it could be that the developing world "catches up" much faster now. Maybe in 10 years, Africa will be more like US 2010 than US 1975.

Latin America is probably the region to look at since it's more developed than Africa but less so than the US and Europe, and has developed dramatically in recent decades. One or two generations ago people still had massive families, but now their rates are falling and in my experience educated, independent women are not particularly interested in having families, or only in having small ones.

I will never have children because of condoms, birth control and now a vasectomy.

My sex drive would not have been less a few generations back. The results would have just been possibly very different.