Shocking. No, really, shocking:

Home prices in 20 U.S. cities fell 19 percent in January from a year earlier, the fastest drop on record, as demand plummeted and foreclosures rose.

The S&P/Case-Shiller index’s decrease was more than forecast and compares with an 18.6 percent decrease in December. The gauge has fallen every month since January 2007, and year- over-year records began in 2001.

There is good news, however:

A glut of unsold properties may keep prices low, shrinking household wealth and damping spending. Still, sales of new and previously owned homes rose in February, indicating the housing slump, now in its fourth year, may ease as policy efforts to unclog credit and aid borrowers begin to take hold.

Well, good:

“There is still a lot of downward momentum,” said Michelle Meyer, an economist at Barclays Capital Inc. in New York. “We don’t think we’ll see a bottom in home prices until the second half of next year. The decline in home prices will continue to depress household balance sheets.”

In other words, don’t buy a new home yet. Wait until next year. And if you already bought on, don’t sell it.