It was the lowest figure since 1998, when 365 forged notes were discovered.

The BOK said the decrease was driven by the arrest of two big-time counterfeiters in the country.

As a result, the number of counterfeit 10,000-won bills (worth around $8.95 each) with the same serial number plunged 77.7 percent on-year. In South Korea, the 10,000-won bill is the most-used note and, behind the 50,000-won note, is the second-highest denomination.

The central bank said 0.12 counterfeit bills were found for every 1 million banknotes in circulation in the country last year, down from 0.3 from a year earlier.

The figure is among the lowest in the world, although it trails Japan's 0.06 ratio, the BOK said. The number for Britain was 129.1, while Mexico had 66.8 counterfeit bills per million. (Yonhap)