Home prices rose for a third consecutive month in July, and the rate of annual decline continued to shrink for the sixth month in a row, according to the Standard & Poor's/Case Shiller home price indices published today.

An index tracking prices in 20 metro areas showed prices increased in 18, by an average of 1.6 percent on a non-seasonally adjusted basis. Looking back a year, the 20-city composite index was down 13.3 percent -- a smaller drop than the 15.4 percent decline seen in June.

The numbers "continue to support an indication of stabilization in national real estate values," David Blitzer, chairman of the index committee at Standard & Poor's, said in a statement.

But it remains to be seen whether the housing market will weather the possible expiration of a tax credit for first-time homebuyers in November, anticipated higher unemployment rates, and a possible increase in foreclosures, Blitzer said.

The 20-city composite index showed prices down 32.6 percent from their peak in second-quarter 2006, to levels last seen in fall 2003.

The five markets in the 20-city composite showing the strongest month-over month price increases were Minneapolis (4.6 percent), San Francisco (3.3 percent), Chicago (2.7 percent), San Diego (2.5 percent) and Atlanta (2.3 percent). Two markets saw month-over-month price declines: Las Vegas (-1.1 percent) and Seattle (-0.1 percent).

Looking back a year, all markets in the 20-city composite continue to show price depreciation, although six of those markets experienced only single-digit declines and three are nearing positive territory: Cleveland (-1.3 percent), Dallas (-1.6 percent) and Denver (-2.9 percent).

The five markets with the sharpest annual declines were Las Vegas (-31.4 percent), Phoenix (-28.5 percent), Detroit (-24.6 percent) Miami (-21.2 percent) and Tampa (-18.4 percent). The index showed prices in Las Vegas down 54.8 percent from their August 2006 peak.