A record 720,000 people reported incomes of W100 million or more last year, the National Tax Service said Thursday in its annual report.
Som 130,000 people reported capital gains of at least W20 million, 40,000 more than in 2016, but the number of those who paid no taxes because their income was so low remained high at 7.39 million (US$1=W1,121).
Based on data from the 18.01 million people who filed their tax returns, the average salary was W35.19 million, up 4.7 percent from 2016.
But income polarization is growing, with a 10.1 percent rise in the number of people who earned W100 million or more to 719,000. That is an increase of 52 percent from 2013, though the tax regime was much laxer at the time.
Yet the number of workers who paid no taxes on their low incomes stood at a whopping 7.39 million or 41 percent of all workers.
The number of day laborers rose by 11,000 from a year earlier to 8.17 million, most of them employed in the construction sector. Their average yearly income stood at a paltry W7.93 million, although it went up 4.2 percent on-year.
The number of foreign laborers slightly dipped to 558,000 last year. They earned a combined W14 trillion, and their average annual pay rose W1.1 million to W25.1 million over the period. One-third were Chinese, followed by Vietnamese, Indonesians and Filipinos.
Some 1.28 million people started their own businesses, with Suwon, Gyeonggi Province, accounting for the biggest chunk with 22 percent or 289,000. Fifteen of the top 20 places for new businesses were around the Seoul metropolitan area.
A combined 479,000 people started service or retail businesses, with 18 percent or 86,677 opening Korean restaurants. Other popular ventures were mobile phone shops, real estate agencies, clothing stores and coffee shops.