Although Philadelphia's seven-year population decrease came in second only to that of Hurricane Katrina-ravaged New Orleans in terms of raw numbers, "it's 13th when you compare the percentage of population decline, which is a more appropriate indicator," Mark Schweiker, president and CEO of the Greater Philadelphia Chamber of Commerce, tells GlobeSt.com.

He adds, "while the population has been shrinking in Philadelphia since 2000, it's important to note that it's declining at a much slower rate." Between 2000 and 2001, Schweiker says, the city lost 1% of its population, but between 2006 and 2007 the rate of decline had tapered off to 0.25%.

The census bureau estimates that Philadelphia lost 67,916 residents between 2000 and 2007, a 4.5% population decline that exceeded that any city in the top 25. During this time, Philadelphia slipped from fifth to sixth largest US city behind Phoenix, which has a population estimated at 1.52 million compared to Philadelphia's 1.45 million. That compares to a loss of 245,550 residents in New Orleans, occurring mostly in the wake of Katrina. Interestingly, last year New Orleans' population began rebounding, increasing nearly 14% between 2006 and 2007.