NEW YORK — U.S. home prices tumbled in April at the fastest rate since a widely followed index was begun in 2000 with all 20 metropolitan areas surveyed posting annual declines for the first time.

The Standard & Poor's/Case-Shiller home price index of 20 cities fell by 15.3 percent in April versus a year ago, according to Tuesday's report. Prices nationwide are at levels not seen since August 2004.

The narrower 10-city index declined 16.3 percent in April, its biggest decline in its more than two-decade history.

Meanwhile, a report from the Office of Federal Housing Enterprise Oversight said U.S. home prices fell 4.6 percent in April from the same month last year, when the index peaked.

The government index is calculated using mortgage loans of $417,000 or less.

While the government report has shown nationwide price declines, the Case-Shiller index has shown far greater drops because it focuses on larger cities where prices rose further during the boom years, and includes riskier loans.

No surveyed city stayed above water, according to the Case-Shiller index. The last holdout, Charlotte, N.C., finally succumbed to the national housing downturn, with prices there slipping 0.1 percent from a year ago.

Las Vegas and Miami both continue to post the largest declines, falling 26.8 percent and 26.7 percent, respectively.

However, the annual declines in Denver, Dallas and Cleveland were less severe than in the previous month, but Maureen Maitland, a S&P vice president, is reluctant to peg that as an indication of stabilization.

"We wouldn't call a trend on one-month data," she said.

The report also showed prices in eight metro areas increased in April from March, but the gains could be seasonal blips as the home-buying spring season starts up rather than a sign of a turnaround, Maitland said.

The housing slump, along with higher food and fuel prices and disruptions in the credit markets, has taken its toll on consumer sentiment.

An industry group Tuesday said U.S. consumer confidence fell unexpectedly sharply in June to the fifth-lowest level ever. The Conference Board's reading of consumers' expectations also hit an all-time low.