U.S. home prices in the first quarter posted double-digit gains over the same quarter of 2012, a closely watched private report said Tuesday. The Standard and Poor\'s/Case-Shiller home price report said its 10-city index rose 10.3 percent from January through March of 2012. Over the same period, the report\'s 20-city index rose 10.9 percent. The national composite index rose 10.2 percent over the same time period, the report said. All 20 of the report\'s monitored cities posted increases year-over-year. From February to March, the 10-city index and the 20-city index rose 1.4 percent with five cities -- Charlotte, N.C.; Los Angeles; Portland, Ore.; Seattle; and Tampa, Fla. -- posting their largest month-over-month gains in five years. \"Home prices continued to climb. Home prices in all 20 cities posted annual gains for the third month in a row. Twelve of the 20 saw prices rise at double-digit annual growth. The National Index and the 10- and 20-City Composites posted their highest annual returns since 2006,\" said David Blitzer, chairman of the Index Committee at S&P Dow Jones Indices, said in a statement. In March, Phoenix posted the largest annual gain with prices up 22.5 percent. The second sharpest gain was in San Francisco at 22.2 percent, followed by Las Vegas at 20.6 percent. Atlanta posted a gain of 19.1 percent and Detroit a gain of 18.5 percent. The lowest gains were in New York at 2.6 percent, Cleveland at 4.8 percent and Boston at 6.7 percent.