Each year more Americans are born than die, and more people move here from abroad than emigrate to foreign countries. So most municipalities see their populations grow. If you're shrinking, something is really going wrong.
But some places are shrinking. These are the 25 cities that, according to the most recent Census data, are witnessing their populations shrink the fastest. Only cities with at least 50,000 residents are counted.
Note that eight of the unlucky 25 are in Michigan and that pin near Philadelphia is actually Camden, New Jersey right across the border.
Population shrinkage can be a big problem for cities since there's always a risk of setting off a self-reinforcing trend. A given municipality is bound to have a fair number of fixed costs (pensions, upkeep on roads and government buildings) that don't scale down when the population shrinks. That leaves the remaining population to either suffer higher taxes or reduced levels of public services, either of which further encourage population flight. This is one of the core problems in Detroit which simply doesn't have enough people any longer to pay the fixed costs of a city built for many, many more.