The number of educated millennials living in Center City ballooned 78 percent between 2000 and 2010, according to a report released Monday.

"The Young and Restless and the Nation's Cities," published by cityobservatory.org, found that 25 to 34 year olds with at least a bachelor's degree have been flocking to major metropolitan areas, fueling economic growth and stimulating urban revitalization.

Philadelphia ranked sixth among major cities which have attracted young college graduates to their booming city centers. New York City topped the list followed by San Francisco, Washington D.C., Chicago and Boston.

The trend was "nearly universal" in all major metropolitan areas, the report stated. Among the the largest 51 metropolitan areas in the U.S., only Detroit saw a decrease in the demographic.

In the Philadelphia metropolitan area, the number of educated young adults grew at a slower rate increasing by a still substantial 22 percent. The metropolitan area extends to Coatesville in the west to Tom's River in the east and also encompasses Wilmington and Newark to the south and Trenton and Quakertown north of the city.

But the most phenomenal growth occurred within a three mile radius of Center City in the so-called "close-in urban neighborhoods," according to the report. More than 50,000 young college graduates were concentrated in those neighborhoods in 2010 up from about 28,000 in 2000.

Previous studies, notably "Millennials in Philadelphia by the Pew Charitable Trusts," have also noted the explosion in the demographic. However, the Pew study cast doubt on whether the trend could be sustained. In an accompanying poll, released in January, the majority of those millennials said they likely would move out of the city in the next 5 to 10 years. The reason: a need for better schools and better career opportunities.

According to a January report in the Inquirer, only 36 percent of the millennials surveyed would recommend Philadelphia as a place to raise children.

Pew's conclusion:  "With many young adults starting to raise families or thinking about doing so, this view is not a positive sign."