“The one disconcerting thing about the number is the rate that prices are falling is accelerating,” said Patrick Newport, an economist at Global Insight, a research firm outside Boston.

The housing market will probably exert significant influence on the health of the broader economy in the coming year. In recent months, growth has slowed but strong exports and rising wages have offset some of the weakness in housing and the financial markets. Consumer spending in the holiday season has been weaker than some retailers had hoped, though reports indicate it is still growing.

“It has been surprisingly resilient,” Robert J. Shiller, the Yale economist and a creator of the home price indexes, said about the economy. He added that it was difficult to determine what impact the weakness in housing would have on the economy going forward. “We are in uncharted territory,” he said. “This was the biggest housing boom we have ever seen.”

By Mr. Shiller’s calculation, the decline in home prices is greater than at any time since 1941 when the housing market was faltering at the start of World War II. Since their peak in July 2006, home prices in the 20 regions have dropped 6.6 percent. Many economists are predicting that home prices will fall 10 percent to 15 percent from their peak to their trough, though some pessimists believe the drop could be as large as 30 percent.

Prices are dropping fastest in the Midwest, which has been hit hard by job losses in manufacturing, and in California, Florida and the Southwest, where the housing boom was at its frothiest. Prices have fallen the most in Miami (12.4 percent from a year ago), Tampa (11.8 percent) and Detroit (11.2 percent). Prices are also falling in the nation’s two largest metropolitan areas  Los Angeles (8.8 percent) and New York (4.1 percent).