Experts say foreclosures have contributed to falling prices. (Creative Commons)

In a report that looked at 20 of the largest U.S. metropolitan areas, including Phoenix, Los Angeles, Tampa, Seattle, New York, and Washington D.C., S & P concluded that the housing prices fell by 4.2 percent in the first quarter of 2011, plunging to a level not seen since 2002.

“Home prices continue on their downward spiral with no relief in sight,” David M. Blitzer, chairman of S & P committee examining the findings, said in the company’s official statement.

Of the cities studied, Washington was the only metropolis to see growth this March and in 2010, the New York Times reported.

Home prices fell all but two of cities profiled between February and March, and the study indicates the decline has been steady since this time last year.

Economists are calling the decline a “double-dip”, since prices reached their previous low in April of 2009.

There are a number a factors contributing to the decline, they say, including continued unemployment, the appeal of renting versus buying in an unstable market, and the affordability of foreclosed properties.

The decline could trigger a vicious cycle, in which more loans are defaulted on and more homes are foreclosed upon, said the Los Angeles Times.

Among the cities included in the report, all the cities save Washington posted a decline since 2010, and all but eight showed new lows for March of this year.