[msl]

How much better do you think public transportation is in the US (35 people per square kilometer) than in Finland (16 people / km²) or Sweden (24 people / km²)?

While you're checking the provided citation, you might want to compare those countries' fertility rates too (and others as well, of course – France's for instance is quite a bit higher than that of the US': 1.82 vs. 1.67). You have yet to demonstrate that your hypotheses are well supported by data.

[1] https://en.wikipedia.org/wiki/List_of_countries_and_dependen...