The number jumped 11.7 percent, or 16,000, to 150,000 in the first three months this year from a year earlier, according to the official tally.

The rise is the sharpest since the second quarter of 2007, when a 12.8 percent increase was posted.

The number of unpaid male workers at their family businesses has climbed gradually for the four consecutive quarters since the second quarter last year, with the increase rate standing at 1.6 percent for the second quarter, 1.9 percent for the third and 6.9 percent for the fourth.

The number of self-employed people soared by 170,000 in the first three months this year, with roughly half of businesses they run posting sales of less than 3.8 million won ($3,346) per month. (Yonhap)