Home prices strengthened in major U.S. metros in the second quarter, pushing home affordability levels down a bit from the first quarter, according to the National Association of Home Builders/Wells Fargo Housing Opportunity Index.

The latest index shows 73.8% of all new and existing homes sold in 2Q were affordable to families earning the national median income of $65,000. That affordability rate is down from the first quarter when 77.5% of homes were slated as affordable to median-income earners. 

The study says 92% of all metros covered noted a rise in the median home prices between the first and second quarter. 

"While interest rates and overall housing affordability remain very favorable on a historic basis, the decline in the latest HOI is a positive development because it is another signal that the housing recovery is starting to take root, and it lends needed confidence to prospective buyers and sellers who have been reluctant to move forward in the current marketplace," said NAHB chairman Barry Rutenberg.

The most affordable housing market in 2Q was the Youngstown-Warren-Boardman, Ohio-Pa. market, where 93.4% of homes sold were affordable to families with income levels in the $55,700 range.

The least affordable market is the New York-White-Plains-Wayne, N.Y.-N.J. area. Only 29.4% of homes sold in that market were affordable to families earning the area's median income of $68,300.

Ocean City, N.J., meanwhile, is the least affordable smaller market with only 43.8% of homes sold in the second quarter affordable to families earning the median income of $71,000.