By Pat Loeb

PHILADELPHIA (CBS) — Philadelphians have gotten a lot more mobile in recent years, and a new study by the Pew Trusts has found some intriguing patterns.

Analyzing census and IRS data, Pew’s Philadelphia Research Initiative finds two-thirds of the people moving into Philadelphia are between 18 and 34, but that age group makes up less than half of those moving out of the city.

Executive Director Larry Eichel says that’s making the city younger.

“The median age of the city has been dropping,” he says, “and it’s been dropping primarily because of an increased population of young adults.”

He says those moving in and those moving out tend to be whiter, with higher educational attainment, than the city as a whole, while those who move within the city look more like the general population.

The study shows most people move in from or out to nearby suburbs, but for those who leave the region, the top destinations are New York City and Austin, Texas.