Sales of North American-made vehicles tumbled 20.4 percent in late November compared with last year, mainly because of a sharp slump in truck sales.

The decline and recent announcements of production cuts for the rest of the year reflect a slumping auto industry as the U.S. economy softens.Among the Big Three automakers, Ford Motor Co. suffered the most, but General Motors Corp. and Chrysler Corp. didn't fare much better.

Late November sales of Ford vehicles dropped 30.1 percent, GM's sales fell 22.5 percent and Chrysler's were down 17.4 percent.

Combined, the Big Three and the seven Japanese companies making cars and trucks in the United States reported they sold an average of 29,510 vehicles during the Nov. 21-30 period this year, compared with a daily rate of 37,062 during the same time last year.

The Big Three automakers held 68.3 percent of the market for the month.

Light truck sales fell 28.5 percent and car sales dropped 15.2 percent.

"Sales have been fairly good this summer and fall," said auto analyst David Healy of the investment firm Barclays de Zoete Wedd in New York. "That thump you heard was car sales falling out of bed."

The late-November car sales rate was among the lowest of recent history, he said.