SEOUL - Kia Motors, South Korea's second-biggest carmaker, posted a double-digit increase in its 2018 earnings due to a low base effect, the company said Friday.

Kia's revenue rose 1.2 percent over the year to 54.2 trillion won ($48.3 billion) in 2018 due to an increased car sale and a higher product price.

Operating profit jumped 74.8 percent to 1.2 trillion won ($1.1 billion) in 2018 as the one-off labor costs disappeared last year. Net income advanced 19.4 percent to 1.2 trillion won ($1.1 billion).

Kia sold a total of 2,809,205 vehicles in 2018 at home and abroad, up 2.4 percent from the previous year. Car sales in the domestic market gained 2 percent to 528,611 units, while its overseas sales increased 2.5 percent to 2,280,594 vehicles.

During the October-December quarter, Kia's revenue climbed 3.6 percent to 13.5 trillion won ($12 billion) compared with the same period of last year.

Operating profit jumped 26.3 percent to 382 billion won ($340 million) in the December quarter, but net income retreated 10 percent to 94.3 billion won ($84 million) on foreign exchange loss.