The largest demographic in Philadelphia now is people 25 to 29. Maybe they don't trust anyone older than 30. (Yet.) There's 144,336 of them, closely trailed by 144,114 in the 20 to 24 slice. By contrast, there are only 92,635 in the 55 to 59 age group (baby boomers). Millennials are one-quarter of Philly's population.
Older people like Philly more and are less likely to leave. Is this because the elders are happier, or have thrown in the towel on prospects elsewhere? Unlike their elders, more of the millennials came from elsewhere, arrived in recent years and are concentrated in youth zones of Manayunk, Center City, University City and Fairmount.
Other hot "young" neighborhoods include northern South Philly (think about the East Passyunk explosion), Northern Liberties and the artistic precinct of Fishtown/Kensington. Millennials deserve our gratitude for revitalizing these once low-rent neighborhoods.
Manayunk has the highest percentage of youth, an astounding 59.1 percent (to the annoyance of native Yunkers), while Cedarbrook has the lowest, 15.9 percent, which means it can market itself as a retirement community.
As to what would drive the millennials to leave, the top three concerns are job/career, 38 percent; schools, 29 percent; and crime/safety, 22 percent.
Their last concern um, concerns me because Philadelphia is a safe big city. Yes, during the period studied the homicide rate ran high, but not where the millennials live.
I suspect they get their fears from lurid coverage on TV, which 32 percent of them rely on for their information. Only 14 percent name newspapers as their first source, not that we're perfect.
In what seems like a contradiction, millennials are more educated than most of us and poorer than most of us. Maybe they should have learned a trade instead of taking that degree in transsexual studies or post-racial performance art.
Most (56 percent) would not recommend Philly as a place to raise children. That's pretty damning and I guess this is because of poor schools, which follows only poor job prospects as a concern.
If you can't work, you can't live, never mind about the children.
When I moved to Philly in 1966, I would have been right in the middle of their demographic, but we weren't sliced and diced that way then. What brought me here? The Pennsylvania Railroad (R.I.P.).
Seriously, a job lured me to leave my native Noo Yawk, something I thought would never happen, but I'm glad it did because Noo Yawk has been Bloomberged and is not the same place.
I got a raise to come here and when combined with the much lower cost of living, that was a substantial lifestyle improvement.
Philly schools were OK then. Had they not been, I might have remained in Delaware County, where I spent my first year in Pennsylvania.
It's dangerous to generalize from personal experience, but it's foolish to ignore it. We need more jobs, which come from more business, and we need better schools.
Millennials like Philly's affordability, walkability, culture and restaurants. But if it's an economic dead end, how can we blame them for leaving? That's not ingratitude. It's survival.
On Twitter: @StuBykofsky