South Korea\'s terms of trade improved to a three-month high in September as import prices fell at a faster pace than export costs, the central bank said Wednesday. The country\'s net terms-of-trade index for goods -- a gauge of trade terms -- came in at 89.7 in September, up 2.4 percent from a year earlier, according to the Bank of Korea (BOK). The on-year growth rate in September marked the fastest gain since June when the trade terms rose 5.4 percent from the previous year. The index is calculated by dividing the export price index by the import price index. The base year is 2010 with a benchmark index of 100. The BOK said that import prices declined at a faster clip than export costs, improving Korea\'s net terms-of-trade index for goods from the previous year. But Korea\'s income terms-of-trade index, another gauge of trade terms, slightly declined last month from a year earlier as the volume of exports fell on reduced working days due to the Chuseok fall harvest holiday. The income terms-of-trade index reached 109.5 in September, down 0.1 percent from a year earlier, according to the BOK. The index measures how much can be imported with the total export value.