The price of a single-family house in Rhode Island was 25 percent lower in May 2009 than in May 2008, according to the Warren Group, a Boston real estate consulting firm.

The firm, which examines deed records kept by cities and towns, calculated a median sales price of $190,100 in May this year, compared with $252,000 in May last year.

In terms of median sales price, Bristol County fared the best, with a decline of 19 percent. Providence County led the state with a decline of 23 percent.

At the same time, the number of single-family houses sold declined 6 percent, from 677 in May 2008 to 635 in May 2009. The number of houses sold in May is the lowest for the month since 1995, according to Warren Group data.

An unusual aspect of the figures compiled by the firm was the number of bank-owned properties — generally the result of foreclosures — sold in Rhode Island so far this year.

In 2008, from January to May, 6 percent of the single-family houses sold had been owned by a bank. In the same period in 2009, 20 percent were bank-owned. That compares with rates of 8 percent in Massachusetts and 6 percent in Connecticut.

“The sale of distressed homes ... has become a larger share of the residential real-estate market in Rhode Island, especially when compared to other New England states,” Timothy M. Warren Jr., chief executive of the Warren Group, said in a statement.

Condominium prices also followed single-family houses in May, down 28 percent, from $235,000 in 2008 to $170,000 in 2009. The number of condos sold plunged 25 percent in May, from 153 in 2008 to 115 in 2009.

Figures released in June by the Rhode Island Association of Realtors showed a 2.2-percent increase in sales in May for single-family houses and a 24.8-percent drop in median price.

pparker@projo.com