The real estate data and analytics firm CoreLogic reports that home prices in the United States increased in June, marking the fifth consecutive month of year-over-year

gains in residential property values. But the California-based company says price appreciation has slowed considerably – a sign of things to come as we head into the fall season.

According to the CoreLogic Home Price Index (HPI) released Monday, national home prices, including distressed sales, increased by 1.4 percent in June 2010 compared to a year earlier. The company’s analysts also revised the previous month’s numbers upward, indicating that prices in May 2010 rose 3.7 percent compared to the same time last year, as opposed to the 2.9 percent gain previously reported.

CoreLogic says June’s 2.3 percentage point deceleration from May is “very large by historical standards.”

The deceleration was most pronounced in more expensive and distressed segments of the market, the company said. Excluding distressed sales, year-over-year prices only increased by 0.2 percent in June and May’s non-distressed HPI increased by 0.5 percent.

According to Mark Fleming, chief economist for CoreLogic, home price volatility and collateral risk remain very high.

“The stabilization phase and policy intervention since the spring of 2009 has run its course. Prices are expected to further moderately decline as the economy remains weak through the fall,” Fleming said.

Based on CoreLogic’s market data, the five states with the highest appreciation in June, including distressed sales, were:

• South Dakota (+6.9 percent)
• Maine (+6.4 percent)
• California (+5.9 percent)
• Virginia (+4.7 percent)
• District of Columbia (+4.3 percent)

The states with the greatest depreciation were:

• Idaho (-9.1 percent)
• Alabama (-3.8 percent)
• Oregon (-3.5 percent)
• Washington (-3.4 percent)
• New Mexico (-3.2 percent)

Including distressed transactions, CoreLogic says the peak-to-current change in the national HPI, from April 2006 to June 2010, is -28.0 percent.