The number of small business owners has started to decline for the first time in a year and a half, according to Statistics Korea. The bureau said on Wednesday that the figure decreased by 21,000 in January compared to the same month last year. It had been increasing since August 2011 as more baby boomers -- those who were born between 1955 and 1963 -- started to retire and opened their own small shops.

The number of small business owners steadily decreased from 5.97 million in 2008 to 5.39 million in the first quarter of 2011 due to the economic slump following the global financial crisis but began to rise again from August 2011 as the economy rebounded. It then continued to increase by more than 100,000 every month until last October before the growth slowed significantly.

Experts cite the prolonged economic recession as a main cause. "More and more baby boomers are retiring, leading to an increase in the number of potential start-ups, but many of them are having second thoughts about starting their own businesses due to the unfavorable economic conditions," said Lee Joon-hyup at the Hyundai Economic Research Institute.

In fact, the number of start-ups in restaurant and lodging, the favorite sector among aspiring shop owners, dropped in December concurrently with the number of small business owners in their 50s, the largest age group among baby boomers.