" The simple measure of sanity in housing prices, Zelman argued, was the ratio of median home price to income. Historically, in the United States, it ran around 3:1; by late 2004, it had risen nationally, to 4:1. “All these people were saying it was nearly as high in some other countries,” says Zelman. “But the problem wasn’t just that it was four to one. In Los Angeles it was ten to one and in Miami, eight-point-five to one. "

― Michael Lewis , The Big Short: Inside the Doomsday Machine