The number of self-employed people in the nation grew by more than one-point-eight million in the past five years while their average income slipped every year.

According to data obtained by main opposition Democratic Party Rep. Yang Kyung-sook from the National Tax Service on Tuesday, the number of people who run their own businesses amounted to nearly six-point-57 million in 2021, climbing from four-point-72 million in 2017.

The number of such people climbed more than 19 percent in 2021 alone, or about eight times the growth posted among salary earners during the same period.

The data found that despite the rising number of the self-employed every year, their average annual income fell from 21-point-seven million in 2017 to 19-point-five million in 2021.

The drop in income was particularly apparent among small business owners, with the bottom 20 percent of self-employed people by income seeing their average pay slip by 55 percent from 2017 to 840-thousand won in 2021.