

People also generally need support if they are to have kids.
If you have a cultural expectation that people need to move out when they are of age, they can’t rely on grandparents or extended family to look after the children, and if they are spending all their other time working, they’re just not going to have the time to find someone to have kids with, or be able to actually raise the children.
In the absence of other factors, like needing the kids to help out on the farm, people have no reason to have them. Especially in countries like the US, where healthcare and childcare are quite expensive. A childbirth alone is about $3000 - $30000 over there, to say nothing of health-care costs, complications, there being very little parental leave, or any of that.
Do they account for changing economic factors as well? I would be curious about how many of the new diagnoses are from people who might have died from other causes, or been classified that say.