Housing prices have now risen for the last year in more than half of major U.S. cities, marking a milestone in the historic housing collapse that set off the 2007-2009 recession and now may be nearing an end. The S&P/Case-Shiller home price index rose 2.2% in May, beating economists' forecasts, as all 20 of the nation's largest metropolitan areas posted gains from April. More important, 12 of the 20 cities now have higher prices than they did a year ago, suggesting that the improvement is durable, the report said.