Southern California house and condominium prices fell 17% in August from a year earlier as sales of foreclosed properties pushed down values, MDA DataQuick said.

The median price dropped to $275,000, from $330,000 a year earlier, the San Diego research company said in a press release Tuesday.

The number of homes sold rose 11% from a year earlier, to 21,502 in Los Angeles, Riverside, San Diego, Ventura, San Bernardino and Orange counties.

"There's still a lot of uncertainty out there about prices, interest rates and the availability of mortgage money," said John Walsh, MDA DataQuick's president.

Foreclosures accounted for 39% of sales, down from 41% in July and from a peak of 57% in February, the research company said.

The share of distressed properties may rise in coming months amid increasing defaults in the region, MDA DataQuick said.

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