Average petrol prices in South Korea have dropped to a little below 1,700 won ($1.53) per liter, according to data by Opinet, an online service provider of oil prices run by the state-run Korea National Oil Corp.

Opinet said Thursday that this was the first time in four years that the nation’s average gas prices have dropped below 1,700 won.

The agency attributed the latest fall to a decline in international oil prices triggered by the Organization of the Petroleum Exporting Countries’ unwillingness to cut oil supply. The move, which is reportedly designed to squeeze the shale supply of the United States, is expected to continue keeping a lid on global oil prices for the time being.