Home prices in the United States have declined for two months in a row, according to CoreLogic's market index, after rising for the first seven months of the year. The latest CoreLogic Home Price Index (HPI) shows that national home prices, including distressed sales, declined 2.79 percent in September 2010 when compared to September 2009. That follows a drop of 1.08 percent in August 2010 from a year earlier. All but seven states saw a decline in residential property values during the month of September.