The South Korean currency strengthened the most among 27 major currencies this year.

According to data from the Bank for International Settlement on Sunday, the won’s real effective exchange rate index was marked at 122-point-34 at the end of February, up three-point-two percent from 118-point-53 at the end of last year.

The February figure represents the highest since May 2015 and marks the highest growth rate among 27 major currencies including the United States dollar.

The Australian dollar came in second with a rise of two-point-six percent, followed by the currencies of Sweden, Mexico, and Canada.

The real effective exchange rate is the weighted average of a country's currency, relative to an index or basket of other major currencies, adjusted for the effects of inflation.

A reading above the benchmark 100 indicates a currency is overvalued, while a reading below the mark indicates undervaluation.