The volume of South Korea’s exports increased thanks to semiconductors and cosmetics, but their value decreased last month due to low oil prices.

According to the Bank of Korea(BOK)’s preliminary data on the country’s terms of trade index revealed on Monday, the export volume index marked 141-point-62 last month, up three-point-nine percent year-on-year.

The index also posted a growth for the second straight month in June, increasing from 135-point-27 in April to 136-point-51 in May.

Exports of chemical products increased 15-point-eight percent on-year, while those of electrical and electronic equipment expanded nine-point-four percent on-year. However, exports of transportation equipment and machinery decreased eight-point-three percent and seven-point-two percent, respectively.

The central bank’s export volume index reflects price differences of products without simply adding up the weight of products. It does not include ships, weaponry, aircraft and art works.