It's down everywhere with world just hanging there at the rate of 2.2. Even India is now below replacement at 1.94.
So, it's not about money, it's something else. I blame smart phones, and the internet, that have caused decrease in real human interaction. Just think about how youth spent time in the 90's - by hanging around in city centers, malls etc.
In the past you had to have certain amount of money to have smart phone and internet, that is why it hit richer countries first. Now they are available for everyone.
I think we need to think about how to get people to same spaces, such as having our teenagers in same classrooms (for example now we tend to segragate campuses according to main subject, such as tech (guys) vs health (girls).