DETROIT — Ford Motor Co. says its U.S. sales plummeted 32 percent in December as buyers continued to steer clear of showrooms due to economic uncertainty.

Ford’s sales for the full year dropped 21 percent, making it likely that the Dearborn, Mich., company will trail Toyota Motor Corp. and remain the No. 3 U.S. auto seller for the second straight year.

Toyota and other automakers report December and full-year sales later Monday.

Ford says it sold 138,458 light vehicles last month, down from 204,787 vehicles in December 2007.

For the entire year, Ford sold about 2 million vehicles, more than half a million fewer than in 2007.