SEOUL, Sept. 27 (Xinhua) -- South Korea's export volume fell for the second successive month due to lower demand for oil products, central bank data showed Wednesday.

The export volume index dipped 0.6 percent in August from a year earlier after retreating 3.3 percent in the previous month, according to the Bank of Korea.

In terms of volume, outbound shipment for coal and oil products plunged 27.4 percent while export for farm goods and transport equipment advanced in double figures.

The export value index declined 9.5 percent in August from a year earlier, continuing to slide for the 11th consecutive month.

The import volume index dwindled 12.1 percent in August from a year earlier after going down 10.6 percent in the prior month.

The import value index dropped 23.3 percent last month and kept a downward trend for the sixth straight month.

The net terms-of-trade index for goods, which gauges the amount of import that can be bought with a unit-export proceed, gained 4.4 percent in August from a year ago, owing to a faster fall in import prices than export prices.