Less than half of U.S. cities are affordable for people who earn a median income

Less than half of U.S. cities are affordable for people who earn a median income:   Most big American cities are no longer affordable for the average worker.:  

http://www.marketwatch.com/story/less-than-half-of-us-cities-are-affordable-for-people-who-earn-a-median-income-2014-11-14