Home prices across the nation increased 1.3% on average when comparing both of Standard & Poor's Case-Shiller price indices to year-ago levels, S&P said Tuesday.

The latest report from S&P Case-Shiller shows new price data breaking seven months of falling home prices – a negative trend that lasted through March when the 10-city and 20-city composite indices fell more than 2.5% from a year earlier.

In April, both city composites indices reported year-over-year declines in home prices, but neither drop was as steep as March. For example, the 10-city composite index fell by 2.2% year-over-year in April, while the 20-city composite fell by 1.9%. This compares to price declines of 2.9% and 2.6%, respectively, for the 10- and 20-city indices in March.

S&P says 18 of the 20 metropolitan areas surveyed saw increases in annual price returns in April. Only Detroit and New York performed worse in April. 

"With April 2012 data, we finally saw some rising home prices," said David Blitzer, chairman of the index committee at S&P Indices."On a monthly basis, 19 of the 20 MSAs and both composites rose in April over March. Detroit was the only city that saw prices fall, down 3.6%. In addition, 18 of the 20 MSAs and both composites saw better annual rates of return. It has been a long time since we enjoyed such broad-based gains. While one month does not make a trend, particularly during seasonally strong buying months, the combination of rising positive monthly index levels and improving annual returns is a good sign."

Atlanta, on the other hand, reported double-digit negative annual returns for the seventh month in a row, with home prices falling 17% year-over-year. Cities that saw positive annual returns in home prices included Boston, Charlotte, Dallas, Denver, Detroit, Miami, Minneapolis, Phoenix, Tampa and Washington D.C.