The credit crisis continued to drive down Rhode Island’s real-estate prices last month, with buyers snatching up distressed houses at steep discounts, according to a report released today by the Rhode Island Association of Realtors.

The most dramatic drops were for multifamily houses, as banks, seeking to unload houses in foreclosure or “short” sales (designed to avoid foreclosure) slashed prices.

As a result, sales of multifamily houses in July jumped 28.7 percent from a year ago, and the median price plunged 45.7 percent, to $140,000, down from $258,000 in July of last year. Just over 70 percent of the 148 multifamily houses sold last month — 104 houses — were foreclosures or distressed sales, the report said. The median price of the other 44 “conventional” multifamilies sold was $232,450, the report said.

Prices of single-family houses also declined, but not enough to boost sales. The median price of a single-family house in July fell to $245,000, down 12.5 percent from $280,000 in July of last year. Sales of single-family houses in July declined 4.9 percent from the same month last year, the report said.

More than one in four single-family house sales in July — 26.3 percent — were foreclosure or short sales, the Realtors reported.

July marked the third consecutive monthly decline in house listings — a sign of “continued recovery,” the Realtors report said. The decline in the number of unsold houses is “critical to restoring balance to supply and demand in the market.”

Yet, the decline in house listings has been more than offset by the lower pace of sales. At the current rate, it would take 12 months to sell all 6,750 single-family houses listed last month with real-estate agents, compared with 10 months for the 6,862 listings in July of last year, according to a Journal analysis of the Realtors data.

House sales averaged 550 per month during the first seven months of this year, compared with 665 per month during the same period last year. (The data does not include sales by owners.)

Meanwhile, condo sales in July tumbled 35.1 percent, to 113 sales, down from 174 sales in July of last year, according to the Realtors. (Only nine of the condos sold in July involved distressed properties, the report said.) The median price of a condo in July ticked down 1.9 percent in July, to $225,000.

In Massachusetts, house prices and sales last month also continued their descent. The median price of a single-family house in the Bay State in July fell 10.7 percent, to $326,500, and sales declined 10 percent, according to a report released yesterday by the Massachusetts Association of Realtors.

The median condo price last month declined 1.9 percent, to $284,900, and sales were off by 35.1 percent from a year ago, the report said.

The Realtors in both Massachusetts and Rhode Island reported that declining prices and the federal government’s $7,500 homebuyer tax credit are making more properties affordable for first-time homebuyers.

In Rhode Island, first-time homebuyers make up more than 40 percent of the housing market, so they are “critically important to the market recovery,” said the Rhode Island Association of Realtors report.

R.I. real estate Single-family Sales:

larditi@projo.com