Seoul, Oct 15 (IANS): South Korea's export volume grew for the 13th successive month in September due to strong demand for locally-made oil and tech products, central bank data showed on Tuesday.

The export volume index gained 3.9 per cent in September from a year earlier, continuing to expand since September last year, according to the Bank of Korea (BOK).

In terms of volume, outbound shipments for computers, electronic and optical devices, including semiconductors, increased 5.7 per cent in September every year, keeping an upward trend for the 14th straight month.

Export volume for coal and oil products advanced by 9.7 per cent, but those for chemical products, electrical equipment and machinery were reduced by single digits, Xinhua news agency reported.

The export value index climbed 5.0 per cent in September compared to the same month of last year, lower than an increase of 8.2 per cent in the previous month.

The import volume index added 2.4 per cent in September from a year earlier, while the import value index was up 2.1 per cent in the cited month.

Net terms-of-trade index for goods, or a ratio of export prices to import prices, gained 1.4 per cent in September from a year earlier owing to export price growth.