Hyundai Motor Co. and its smaller affiliate, Kia Motors Corp., saw their combined sales in the United States grow 7 percent in December, thanks to a nearly 20 percent jump in Kia's sales, industry data showed Tuesday.

The two South Korean auto giants sold a combined 117,749 units in the U.S. last month, up from 110,094 units during the same period last year, the data showed.

Hyundai's sales fell slightly from a year earlier, logging 63,508 units, a 1.5 percent drop from last year's 64,507. But Kia's sales jumped a whopping 19 percent to 54,241 units from 45,587 of last year, according to the data.

For all of 2015, both Hyundai and Kia said they had the best-ever annual sales in the U.S.

Hyundai sold a total of 761,710 units in 2015, up 5 percent from last year, while Kia sold 625,818 units, a 7.9 percent rise from last year.

"Hyundai once again experienced a record year and the CUV (crossover utility vehicle) segment proved to be the star," said Derrick Hatami, vice president of national sales for Hyundai Motor America. "Not only did Tucson end the year with sales up 34 percent, but for the month of December we experienced a 167 percent sales gain over last December. For the year, Santa Fe was up nine percent."

The Tucson sold 63,591 units for all of 2015, up from 47,306 in 2014. In December alone, its sales more than doubled to 8,311 units from 3,114 of last year.

Kia said that 2015 mark the first time its annual sales in the U.S. topped the 600,000-unit mark.

"Even without the benefit of a truck in our lineup, Kia began 2015 as one of Yahoo!'s 'hottest brands' and it only got better from there as we outperformed the record-setting industry and posted big gains in several passenger car and CUV segments," said Michael Sprague, chief operating officer of Kia Motors America. (Yonhap)