[chabska]

Because "current residents" also include the children and teenagers currently living there? You act like young adults are 100% flown in by storks, as if the city doesn't itself procreate, as if school children doesn't grow up into young adults.

[floxy]

Any good sources showing how much various cities' fertility rate contributes to their population growth?

[lotsofpulp]

They don’t contribute, as they are all below replacement rate.

https://www.newgeography.com/content/007550-total-fertility-...

Probably true worldwide except maybe Africa and Middle East.