The U.S. trade deficit narrowed sharply in December because exports rose while oil imports plummeted. The smaller trade gap means the economy almost surely grew in the October-December quarter — an improvement from the government’s estimate last week that it shrank in the final months of 2012.

The trade deficit fell nearly 21 percent in December from November to $38.6 billion, the Commerce Department said Friday. That’s the smallest in nearly three years.