South Korea's terms of trade improved for the fifth straight month on-year in January as weaker oil prices pushed import prices lower compared to export prices, data showed Thursday.

The country's net terms-of-trade index for goods reached 95.82 last month, surging 8.4 percent on-year and hitting the highest level in more than four years. The January gain accelerated from 3.9 percent on-year growth in the previous month.

The index is calculated by dividing the index for export prices by that for import prices. The base year is 2010 with a benchmark of 100.

From a month earlier, the index gained 2.6 percent, rising for a sixth consecutive month and also picking up from a 1 percent rise in December.

The data also showed that the country's income terms-of-trade, which measures how much can be imported with the total export value, reached 126.33 last month, up 14.9 percent from a year earlier. (Yonhap)