Price drops in major metropolitan areas seem to be subsiding, according to the April S&P/Case-Shiller home price index. The data, released Tuesday, noted an 18% annual decline in its 10-city composite, which tracks home prices in Boston, Chicago, Denver, Las Vegas, Los Angeles, Miami, New York, San Diego, San Francisco, and Washington, D.C.

The index’s 20-city composite notched an 18.1% annual drop for home prices in the 10 cities above, plus Atlanta, Charlotte, Cleveland, Dallas, Detroit, Minneapolis, Phoenix; Portland, Ore.; Seattle, and Tampa.

As dramatic as such percentages sound, they represent a tiny improvement over March, when both composites reported an 18.7% annual plunge for housing prices in those markets.

“While one month’s data cannot determine if a turnaround has begun; it seems that some stabilization may be appearing in some of the regions,” said David M. Blitzer, chairman of Standard & Poor’s index committee. “We are entering the seasonally strong period in the housing market, so it will take some time to determine if a recovery is really here.”

In terms of individual markets, Dallas proved to be the strongest performer, with a 1.7% home price gain in April compared to the previous month. On an annual basis, Dallas is down just 5%, which is one of just three single-digit percentage declines among these 20 major metro housing markets. (The other two are Boston, which is down 7.7%, and Denver, which is off 4.9%, compared to one year ago.)

Other Sun Belt cities and their suburbs weren’t so lucky. Las Vegas posted the worst monthly decline (down 3.5%) and the second-worst annual home price plunge with a drop of 32.2%. The first worst? Phoenix, with a 35.3% drop.

Alison Rice is senior editor, online, at BUILDER magazine.