The North American rule of thumb is that young people -- specifically people in their 20s -- are the most likely to to live in an urban neighborhood. After that it's all down hill and, broadly speaking, the percentages decline. But at some point, much later in life, the data suggests that there is a reversal and people start to return to urban neighborhoods, albeit not to the same extent. Part of the explanation for this is that as people age they start to look to more walkable neighborhoods where they don't need to get a car to get around.
But in this recent NY Times article, Jed Kolko points out two interesting trends. One, the "urban boomer" appears to be on the decline in the US. In 1990, about 21.6% of Americans aged 54 to 72 lived in an urban neighborhood (categorized by density). As of 2018, this number had dropped to around 17.8%. And two, the age at which there is a reversal (and people start returning to denser neighborhoods) is also increasing. Perhaps because people are living longer.
Jed's conclusion: American boomers, today, are actually less urban than previous generations.
Graph: New York Times