DETROIT - U.S. auto sales continued their precipitous tumble in December, closing the books on the industry's worst year since 1992.

Five of the Big Six automakers - General Motors, Ford, Toyota, Nissan and Honda - saw sales slide another 30 percent each in December; Chrysler's plummeted 53 percent. Most automakers showed year-over-year declines; the lucky ones saw mere single-digit dips. December's seasonally adjusted annual rate of sales totaled 10.27 million vehicles, down from 15.95 from December a year ago but better than November's 10.14 million.

For the full year of 2008, all of the Big Six automakers reported sales declines. In total, the industry sold 13.2 million vehicles for an 18-percent - or 3-million unit - drop from 2007's 16.1 million.

Thanks to a late-year hike in truck sales, the Ford F-Series pickup maintained its spot as the nation's best-selling vehicle for more than three decades. The F-Series' long-held sales crown had been threatened earlier in the year as industry truck sales plummeted in reaction to $4 a gallon gas. The Chevrolet Silverado ranked second in total vehicle sales, according to Ward's Auto.

The Toyota Camry was the nation's best-selling car, and third in overall vehicle sales. The Honda Accord, Toyota Corolla/Matrix, Honda Civic and Chevrolet Impala followed.

Analysts predict the early going in 2009 will be rough for the auto industry and the full year will be no barnburner, but signs that the bottom is near are evident, notably an improvement in the industry sales rate from October and November to December, albeit through record incentives.

Auto executives also are optimistic that President-Elect Obama's economic stimulus package will boost consumer confidence and outgoing President Bush's bailout to banks will finally loosen credit again - two key factors, they say, driving historically low car sales.