Here are the five housing data trends that you need to know:

1. Housing construction has slumped. - New-home construction starts dropped 14.3 percent from December to January, putting them 37.8 percent below the same time a year earlier. Building permits dropped 28.6 percent from a year ago.

2. Sales volumes are down. - Last month's sales of existing homes were down 4.3 percent from January 2006. There are about 1 million homes on the market.

3. Home builders can't shift their inventory. - Between January 2006 and January 2007, new home sales dropped 20 percent, according to the Commerce Department.

4. Risk premia (i.e. long term mortgage rates) are rising. - The National Association of Realtors predicts the cost of a 30-year fixed mortgage will jump to about 6.6% by the end of the year.

5. Mortgage resets will accelerate.- Of the $8 trillion to $9 trillion in mortgage debt outstanding in the country, a half-trillion dollars' worth is about to be converted to higher interest rates now that introductory teaser periods are expiring