Hyundai and affiliate Kia's revenues from China and the U.S. overtook domestic sales for the first time last year. Hyundai and Kia on Sunday said their combined sales in China totaled 1.34 million vehicles last year, in the U.S. 1.26 million and in Korea 1.15 million.

In 2011, the largest portion of sales still came from Korea, followed by China and the U.S. But the order was reversed when the Korean market shrank 2.3 percent last year.

Their sales in China rose 14.2 percent and in the U.S. 11 percent.

The two carmakers expect sales here in 2013 to be similar to last year's but to rise almost 10 percent in China and the U.S. This makes it likely that China will continue as their biggest revenue source, followed by the U.S. and Korea.

European sales growth has also been noteworthy. Hyundai and Kia have seen their market shares increase sharply in Eastern European countries like Hungary and Slovakia, which have been less impacted by the eurozone fiscal crisis than Western Europe. As a result, revenues from Europe are edging closer to sales in Korea.