U.S. home prices fell 3.9% in the fourth quarter when compared to a year earlier due to lingering unemployment and an oversupply of homes on the sales block, the Federal Housing Finance Agency said Thursday in its seasonally adjusted purchase-only house price index. The FHFA’s index measures home price fluctuations nationwide by studying home sales price data on mortgages acquired by Fannie Mae and Freddie Mac. The purchase index does not include findings on mortgage refinancing. Meanwhile, the FHFA’s all-transactions house price index — a study of data on both home purchases and refinancings — fell 0.8% between 3Q and 4Q and 1.3% over the fourth quarter of 2009. The index also saw declines in 3Q over 2Q. Thirty-five U.S. states saw seasonally adjusted declines during the fourth quarter, while prices rose in the 15 remaining states, according to the FHFA index. Of all the geographic regions surveyed, the New England and Mountain regions experienced the most changes in the fourth quarter, with home prices rising 0.1% in New England and dropping 2.2% in the Mountain region. When looking at the nation’s 25 most populated areas, the greatest fourth-quarter price decline occurred in Arizona’s Phoenix-Mesa-Glendale area, the report concluded. Write to Kerri Panchuk.