An index measuring prices of South Korean exports in the local currency fell for the first time in four months.

According to the Bank of Korea(BOK) on Tuesday, last month’s export price index was 80-point-72, a one-point-five percent drop from February’s 81-point-96. The index is calculated by setting export prices of 2010 as 100.

The drop comes after consecutive increases since December last year when the index rose by zero-point-one percent. The March index is also the lowest ever since June 1986 when it recorded 80-point-70.

But BOK officials said export prices measured in foreign currencies including the U.S. dollar, which are used in the actual transactions, rose for the first time in ten months.