WASHINGTON - Sales of previously owned homes in the United States unexpectedly plunged in January, an industry survey showed on Friday, fresh evidence the housing market has yet to find stable ground.

The National Association of Realtors said that sales fell 7.2 percent to an annual rate of 5.05 million units, sharply below market expectations for a 5.50 million unit pace.

December sales were revised slightly lower to 5.44 million pace from 5.45 million units. Compared to January last year, sales of existing homes were up 11.5 percent.

Today's figure is certainly not good news in terms of sales, said Lawrence Yun, chief economist for the NAR.

(Reporting by Corbett B. Daly; Editing by James Dalgleish)