Housing affordability reached a 10-year low in the second quarter, thanks in large measure to rising prices and interest rates, according to the National Association of Home Builders/Wells Fargo Housing Opportunity Index. According to a release, 57 percent of new and existing houses sold during the quarter were affordable to families earning the U.S. median income of $71,900. The number is down 61.6 percent in the first quarter and is the lowest reading since mid-2008. The national median home price rose to $265,000 from from $252,000 in the first quarter, adding up to the highest quarterly rise in the history of the index. Average mortgage rates increased to 4.67 percent from 4.34 percent during the quarter.