South Korea’s old-age dependency ratio is forecast to surge three-point-seven times over the next 35 years.

According to data by the Organization for Economic Cooperation and Development (OECD) on Sunday, the ratio of the country's elderly population aged 65 and over, compared to the number of people of working age between 20 to 64, is projected to reach 72-point-four percent in 2050.

As of 2015, the comparable ratio was 19-point-four percent.

The data means 100 working-age people would be financially responsible for 72 senior people by 2050.

South Korea placed 32nd in 2015 in terms of the ratio among 35 OECD nations, but its ranking is forecast to soar to fifth in 2050, after Japan, Spain, Greece and Portugal.

South Korea's growth forecast ratio was the highest among OECD nations, whose average was one-point-nine times for the same period.