"I don't know whether it's 15 percent or not, but we're clearly calling for about 7 or 8 percent decline," said Sanders.  "There are some of the Case-Schiller economists are even calling for 10-12 percent decline."

Sanders says the extension of the Bush tax-cuts help the housing market, but it's not enough.

"There was such a huge headwind," said Sanders.  "The number of houses in foreclosure has to come out into the market, and that's going to put pressure.  GDP growth is going up, so there some positive signs but housing sales went up, which is good, but didn't go up enough, which is bad."