Prices of U.S. single-family homes rose by 0.7 percent in February but were down 6.5 percent from a year ago, the Federal Housing Finance Agency (FHFA) reported Wednesday. The regulator's monthly home-price index is 9.5 percent below its April 2007 peak. The index is calculated using purchase prices of houses financed with mortgages that have been sold to or guaranteed by mortgage-finance sources Fannie Mae or Freddie Mac. FHFA regulates Fannie Mae, Freddie Mac, and the 12 Federal Home Loan Banks.