The number of South Korean overseas travelers and foreign visitors here fell for the first time in six years last year amid a reduction in the number of people studying abroad, a government report showed Thursday.

The number of international migrants, referring to those who stay in and out of South Korea for 90 days or more, stood at 1.3 million people in 2015, down 1.7 percent, or 23,000, from a year earlier, according to the report compiled by Statistics Korea. The number involves both foreigners and South Korean nationals who crossed the border after a certain period of time, which excludes short-term visitors.

It is the first time the figure posted negative on-year growth since 2009 when it marked 1.16 million.

A total of 622,000 people left the country last year, up 4.8 percent from a year ago, while the number of entrants dropped 7 percent to 684,000 from a year earlier.

The number of South Korean-passport holders who went overseas edged down 0.5 percent on-year last year, marking the sixth consecutive decline since 2009, while those who returned to their home country dipped 5.3 percent on-year.

Foreigners who came to South Korea for living or long-term business decreased 8.4 percent on-year last year, the biggest on-year decline in six years. The number of aliens who left the country jumped 11.3 percent over the same period.

The statistical agency attributed the decline in South Koreans' departures to a decline in the number of young people in their 20s and 30s, who go overseas for study.

"Most people who go abroad are those in that age group," said the agency. "The number of national departures fell as their population has been on a decline over the recent few years."

Korea has been struggling with a low birth rate and aging.

The chronically low birthrate and aging population is feared to reduce the workforce and drive up welfare costs, undermining the growth potential of Asia's fourth-largest economy.

The country's fertility rate, or the average number of babies that a woman is projected to have during her lifetime, hit a record low of 1.08 in 2005 and has hovered around 1.2 in recent years, despite the government's constant efforts to encourage people to have more babies. (Yonhap)