Single-family home prices in the Boston area dropped slightly in January, a closely watched survey said today, suggesting the battered housing market continues to crawl along the bottom.

In the Boston area, prices were down 2.8 percent from January 2011, dropping to 149.38 from 153.72, according to the S&P/Case-Shiller composite index.

The S&P/Case-Shiller composite index of 20 metropolitan areas nationwide recorded a 3.8 percent decline compared with the year before, in line with expectations and an improvement from December’s 4 percent drop.

"This gives you a little more confidence that the housing market is bottoming because perhaps the most troubling aspect of the recent housing data has been the sagging of the Case-Shiller price index effectively since July 2011," said Cary Leahey, managing director and senior economist at Decision Economics in New York. "The fact that the so-called double dip in home prices is ending gives you a little more confidence that the market could improve over the next year and a half."

The only cities with price increases for the month included Miami, Phoenix and Washington. The last time the national price index increased was April of last year. Average home prices across the country were back to early 2003 levels, the report said.

There was little reaction in financial markets immediately after the data.