The article does not make much sense as it, at least for France. We have a tremendous difference in the adoption of religions by age depending on the religion.

The article does not make much sense as it, at least for France. We have a tremendous difference in the adoption of religions by age depending on the religion. There is no "average". When I was a child in the 80's, I have never heard of Ramadan. My children, same age same school know everything about it. Same for hallal food. When I see people of my age (mid-40) who as Muslims, their religiousness is medium to poor. The next generation is very much different, way more religious. Atheists are more or less the same. Catholics are in decline, except in some places where the tradition is strong (Versailles for instance). So averaging "religion" over a whole country does not yield any sensible results in some countries. In other maybe.