South Korea’s auto exports have decreased for the second quarter in a row.

According to the Korea Customs Service(KCS) on Thursday, the nation’s auto exports recorded nine-point-one billion U.S. dollars in the January-March period, down three-point-seven percent from the same quarter last year.

In terms of the number of units, exports were down six-point-two percent to around 600-thousand.

South Korea’s auto exports posted on-year growth for four consecutive quarters through the third quarter of last year before contracting 16-point-two percent in the fourth quarter of last year.

In particular, exports to the U.S. plummeted 23-point-six percent on-year, the steepest decline in six quarters, although the U.S. remained the biggest importer of South Korean automobiles.

Experts say a lack of new design revamps, fierce competition from foreign automakers, and growing marketing costs were some reasons behind the declining exports to the U.S.