These 13 cities have the biggest scars from the housing crash

Zillow, a leading real estate and rental marketplace, has put out a list of the top housing markets still showing scars from the housing crash.

"Roughly half of American wealth is held in home equity," wrote Zillow Chief Economist Dr. Svenja Gudell in a press release. "Paying off the home mortgage is a key step toward retirement for most Americans, and it's clear from these results that Generation X is further from that goal than older generations because of the Great Recession.

The rankings are based on Zillow's home equity research of more than 50 million homeowners with a mortgage.

Here's the list of the cities still showing scars from the housing crash, ranked by percent of homes in negative equity: