U.S. home prices fell by their worst rate of decline ever in May, according to data released Tuesday.

The Standard & Poor's/Case-Shiller index of home prices in 20 cities declined 15.8% in May from the same month last year. The Los Angeles area saw a 24.5% price decline, a record year-over-year decrease.

The region's home prices in May were down 27.5% from their September 2006 peak, according to the index.

The greater L.A.-area decline from the peak now matches the drop seen in the 1990s real estate downturn but has occurred in less than two years. In the previous real estate cycle, area prices declined more gradually, falling 27% from 1990 to 1996 before stabilizing, according to the Case-Shiller index.

The only regions posting larger percentage drops than the Los Angeles area, which includes Orange County, were Las Vegas, with a 28.4% year-over-year decline in May; Miami, with a 28.3% decline; and Phoenix, with a 26.5% decline.