Led by double-digit sales increases at Fiat Chrysler, General Motors Co., Hyundai Motor Co., Toyota Motor Corp. and Subaru of America Inc., the U.S. auto industry closed out a stellar 2014 with a blockbuster December as U.S. consumers took advantage of year-end deals, lower fuel prices and an improving economy. Light-vehicle sales rose 11 percent in December - slightly above forecasts - and 6 percent for the year.to 16.5 million units.