DETROIT: Fiat Chrysler Automobiles and Nissan Motor Co Ltd on Tuesday each posted double-digit US sales gains in December, with major automakers expected to experience a new record year.

Sales in 2015 were seen topping the previous record in 2000 of 17.35 million vehicles, as low gasoline prices, easy credit and moderate economic growth helped boost the industry.

Fiat Chrysler said sales rose 13 percent while Nissan showed a 19 percent gain over a year earlier.

A poll of 38 economists and analysts by Thomson Reuters yielded a forecast of 18.1 million vehicles sold in December on a seasonally adjusted annualized basis.

The month is expected to show double-digit gains over a year earlier as well as the most vehicles sold in the US market for any December. Also, more vehicles were sold last month than any month in 2015, forecasters said.

The Jeep brand posted a 42 percent sales jump in December, again leading Fiat Chrysler, which sold a total of 217,527 vehicles in the month and 2.24 million for the year, a gain of 7 percent.

Sales for the Nissan Rogue, a crossover SUV, rose 78 percent to about 26,500. SUVs, particularly smaller ones like the Rogue, gained substantially in 2015 as consumers preferred them over traditional sedans.

Fiat Chrysler is the No. 4 seller of vehicles in the US market, and Nissan is sixth.