Has L.A.'s housing profile changed in 20 years?

Economy.com has supposedly looked at what people could afford in major metropolitan areas starting in 1980. This very interesting graph shows Los Angeles, New York, and San Francisco in that time have occupied the lower line of housing affordability when compared to income. The recession years gave a boost to L.A.'s affordability, but starting in 2000, it returned to almost the same level by 2004.