(Bloomberg News) Home prices in 20 U.S. cities dropped in March to the lowest level since 2003, showing housing remains mired in a slump almost two years into the economic recovery.

The S&P/Case-Shiller index of property values in 20 cities fell 3.6 percent from March 2010, the biggest year-over-year decline since November 2009, the group said today in New York. At 138.16, the gauge was the weakest since March 2003.

A backlog of foreclosures poised to reach the market means prices may stay depressed, dissuading builders from taking on new-home construction projects. Unemployment at 9 percent and stricter lending conditions are signs that any recovery in housing may take years.

"With the foreclosure pipeline still full to bursting, it's hard to see this downward pressure on prices abating," said Paul Dales, a senior U.S. economist at Capital Economics Ltd. in Toronto. "I wouldn't be surprised to see prices continue to fall this year and maybe into next year."

Economists surveyed by Bloomberg had forecast a 3.4 percent decline from a year earlier, according to the median forecast of 27 economists surveyed. Estimates ranged from declines of 4.9 percent to 2.8 percent.

Other reports today showed consumer confidence unexpectedly declined in May to a six-month low, and business activity in the U.S. cooled more than forecast.

Stocks rose amid speculation the European Union will pledge further aid to Greece. The Standard & Poor's 500 Index was up 0.5 percent to 1,338 at 10:37 a.m. in New York.

Nationally, home prices decreased 5.1 percent in the first quarter from the same time in 2010, and were down 4.2 percent from the previous three months, the biggest one-quarter decrease since the first three months of 2009. At 125.41, the index was the lowest since the second quarter of 2002.

Greece Boosts Shares

Home prices in the 20 cities fell 0.2 percent in March from the prior month after adjusting for seasonal variations, a ninth consecutive decrease. Thirteen of the 20 areas posted price declines in March from the previous month, led by Charlotte, North Carolina, and Minneapolis.

The year-over-year gauge provides better indications of trends in prices, the group has said. The panel comprises Karl Case and Robert Shiller, the economists who created the index.

Nineteen of the 20 cities in the index showed a year-over- year decline, led by a 10 percent slump in Minneapolis. The exception was Washington, where values climbed 4.3 percent.

Prices in 12 markets dropped to fresh lows in March from their 2006, 2007 peaks: Atlanta, Charlotte, Chicago, Cleveland, Detroit, Las Vegas, Miami, Minneapolis, New York, Phoenix, Portland, Oregon, and Tampa.

'Double-Dip'

"This month's report is marked by the confirmation of a double-dip in home prices across much of the nation," David Blitzer, chairman of the Case-Shiller index committee at S&P, said in a statement.

Further declines in home prices are likely to constrain the consumer spending that makes up 70 percent of the economy, as homeowners feel less wealthy and have little home equity to borrow against.

Reports earlier this month showed the housing market remains depressed as the broader economy slows.

Pending sales of previously owned homes plunged 12 percent in April from the prior month, the National Association of Realtors said last week. The gauge measures contract signings, which typically lead closings by one to two months, a sign existing purchases will slow.

Sales Fall

Sales of previously owned homes, based on closings, fell 0.8 percent in April to a 5.05 million rate, with demand for distressed properties accounting for 37 percent of the total, NAR said last May 19.

The overhang of unsold housing inventory will probably remain an issue for builders and buyers alike. CoreLogic Inc. in March estimated about 1.8 million homes were more than 90 days delinquent, in foreclosure or bank-owned, a so-called "shadow inventory" set to add to the unsold supply of 3.87 million previously owned homes on the market at the end of April.

Builders are gloomy and project demand will remain depressed into next year, Bill Wheat, chief financial officer of D.R. Horton Inc., told a housing conference in New York on May 11.

"We still see housing demand at very weak levels," Wheat said. "It could still be a struggle in 2012."