The central bank said the producer price index, an economic indicator that tracks the prices of goods sold in a country before they reach consumers, had reached 103.75 last month, down 0.2 percent from a month earlier.
The index was seen continuing its downward streak for a fourth consecutive month and hitting its lowest point since January 2018, when it posted 103.58, the BOK said. On an on-year basis, it rose 0.2 percent.
The decline of the index was attributed to lower crude oil prices in November and December. Though crude prices have recently recovered, it will take some time before the index reflects the changes.
The benchmark Dubai crude fell 12.6 percent on-month to an average of $51.32 per barrel in December, according to crude price reporting agency S&P Global Platts.
The January index for gasoline and petrochemical goods tumbled 4.2 percent on-month, the BOK said. The index for agricultural goods and electricity and utility services remained stagnant on-month. The index for services rose 0.4 percent on-month.
By Sohn Ji-young (email@example.com)