In 2011, Ben Stango moved to Philadelphia after college. He's never leaving.

"I'm here for life," said Stango. "It'll take me another 70 years to wrap my hands fully around it, experience everything Philly has. And then I'll die, and it'll be a happy life."

Stango, 27, is one of the thousands of millennials who have fallen for Philadelphia over the past decade, making the city a national leader when it comes to the age bracket.

Census data collected by Chicago-based JLL, a financial and professional services firm, shows the city had a 41.2 percent increase in millennials between 2006 and 2014. That's the fastest growth among the country's 10 largest cities.

The jump translates to 120,600 more millennials during that time period.

For Stango, the Philadelphia offers everything you'd want from a big city – good food, art, and entertainment – with a big bonus.

"You have it in a place that's affordable to live," he said.

Still, Stango is a bit of an outlier.

A 2014 study by the Philadelphia research initiative of the Pew Charitable Trusts, half of those interviewed said they didn't see themselves still living in the city five or 10 years from now.

"The reasons they cite for possible departure are primarily job and career, the sense that their career or their ambitions would take them someplace else and concerns related to child-rearing which obviously includes education," said director Larry Eichel.

While Philadelphia added the most millennials, they don't necessarily make up more of the population compared with other big cities.

Millennials make up 26.5 percent of Philadelphia's population.

In Chicago, they are 27.3 percent of the population. In San Diego, millennials account for 27.6 percent of the population.

After Philadelphia, New York and Chicago had the fastest growth in millennials, followed by Houston.