AutoNation, the national chain of dealerships headquartered in Fort Lauderdale, continues to reap the gains from a rebound in auto sales.

In December, sales of new vehicles jumped 15 percent at AutoNation. For the year, sales were up 20 percent. The new stats are better than the industry-wide numbers out this week, which forecast a 13 percent increase in sales of 2011 totals. That would bring 2012’s tally to 14.5 million new vehicles sold.

The numbers are still well below pre-recession peaks of 17 million set in 2005, but still capture the impact of an improving economy in the nation’s auto showrooms. AutoNation owns dealerships across the country, including South Florida’s Maroone chain.

The company’s stock soared 3 percent Friday to $41.88 a share after the release of the December sales numbers.