>>82827257 (OP)
It's not that the size of the families has shrunk. Mothers still have 2.4-2.6 children on average. It's that the proportion of childless women has gone from 5% to 25% in the last 30 years.
>>82827264
Cause they are the only western country that still act like an expansionist state. It's good for the nation when you win wars against your neighbors. After the Franco-Prussian war the fertility in the German empire boomed ,while in France plummeted for a generation.