Income growth in the top bracket has not translated into rising birthrates in Korea, which is suffering a heavy slowdown in population growth.
The number of salaried workers earning more than W100 million a year surpassed 600,000 as of last year (US$1=W1,068). Also, the average annual wage of all salaried workers stood at W33.6 million, up 3.5 percent from 2015.
But around half of couples who have been married less than five years and make a combined annual income of more than W100 million have no children even though they could afford them. Instead, the statistics suggest an increasing aversion to having children among wealthier couples that has to be explained in ways other than the high cost of childrearing that is often cited.
The figures come from the National Tax Service's annual tax return data published Thursday and Statistics Korea data. The tax returns show that 653,000 out of 17.74 million salaried workers in 2016 earned more than W100 million a year, up a whopping 9.6 percent from 2015.
But data on newlyweds by Statistics Korea, also announced Thursday, show that 36.3 percent of couples who have been married less than five years have no children, up 0.8 percentage point compared to a year ago.
Young couples have on average less than one child at 0.8, which is even lower than the paltry overall rate of 1.17 children per couple. In fact, the more money couples make, the less likely they are to have children. Among couples earning a combined income of W30-50 million, some 33.5 percent are childless. But the rate goes up to 44.5 percent for couples earning a combined income of more than W100 million.
In the W30-50 million bracket, the average number of kids is 0.84, but in the top bracket that shrinks to 0.68.
Park Jin-woo at Statistics Korea said, "Young couples who earn high incomes are either double-income families or have professional jobs, which makes it more difficult to find the time to have children."
Home ownership also plays a strong role in whether couples have kids or not. Among couples who own their own homes, 67.8 percent have children, but among those who rent it is only 60.5 percent.