Hopeful homebuyers in Iowa may consider making a move to Davenport or Bettendorf.The Quad-Cities area of eastern Iowa and western Illinois is the second-most affordable place in the nation to buy a house. That’s according to the National Association of Home Builders’ Housing Opportunity Index, which compares median home prices and household incomes. The survey says 92.1 percent of Quad-Cities households could afford to buy a house in the last quarter of 2001. The index used a median annual income of $52,700 and a median house price of $75,000. The Rockford, Illinois, area – where 95.8 percent of the households were able to afford a house – is the nation’s most affordable housing market.