it's such an underdol do underd. we're fighting for a lot of things here. >> describe what somebody from philly who's middle class feels like to you? >> what is middle class? families who are struggling to make payments, getting their kids into some kind of a school. >> it's common throughout the u.s. but philadelphia's story has a unique twist. in the last 40 years the city has lost a quowrlt quarter of its population, and 40% of that population los loss was the mide class. the middle class has shrunk since 1970 from 60% of the population to 51. but philadelphia's middle class has shrink considerably -- shrunk more than 50%. leark eich -- larry eichel wrote a report on the decline of the middle class. >> from 2000 on it's pretty flat. it seems to have stabilized. >> the middle class is a reflection of the city's mental health. like philadelphia's italian market for the last 100 years. the middle class uses and pays for a city's services and it serves as a stepping-stone for those who want to climb the economic ladde