South Korea's terms of trade rose for the sixth consecutive month in May as export prices rose and import prices fell, central bank data showed Friday. The country's net terms-of-trade index for goods -- a gauge of overall trade terms -- improved 4.9 percent last month from a year ago, following the previous month's 5.3 percent on-year rise, according to the preliminary data from the Bank of Korea. The index shows the amount of imports a country can buy for each unit of exports, with a lower figure meaning worse trade terms. Import prices fell 1.1 percent on-year last month, while export prices rose 3.8 percent. It is calculated by dividing the index for export prices by that for import prices. Source: Yonhap News Agency