For continental US, I believe it was around the 1920's[0] while globally, yes it wasn't until 2007 or thereabouts. From an admittedly superficial review, it has been Africa, India and perhaps(?) China that have been undergoing the most urbanization over the last 100 years. Then again, perhaps it's not urbanization per se, maybe it's more total population size. Homeostasis will find a balance point (if one exists).

[0]https://www.khanacademy.org/humanities/us-history/the-gilded...

[1]https://ourworldindata.org/urbanization#share-of-populations...

granted this only goes back to 1960