SEOUL, Dec. 16 (Yonhap) -- The number of foreign residents living in South Korea reached an all-time high this year, accounting for 3 percent of the country's total population, with Chinese residents forming the largest group, government data showed Friday.

According to the statistics compiled by the Justice Ministry, 1.41 million foreign nationals were living in South Korea as of September this year, up 13 percent from the end of last year.

Though the cross-border migrations into South Korea decreased in 2009 for the first time since Seoul began monitoring the movement in 2000 due mainly to the worldwide economic slump, the trend reversed last year in line with the country's economic recovery, the ministry said.

Migrant workers comprised the largest group of all foreign nationals staying here, accounting for 42.5 percent, the data showed. Around 9 percent of them were illegal workers, the ministry found. By nationality, Chinese ranked first with 53.1 percent, followed by Vietnamese with 11 percent, Filipinos with 5 percent and Indonesians with 4.77 percent, according to the data.

Immigrants married to South Korean spouses formed the second largest group of foreign residents here, taking up 10.1 percent of the total international population in the country. Chinese ranked first, totalling 45.4 percent of all spouses, followed by Vietnamese with 25.35 percent, Japanese with 7.64 percent, according to the data. Foreign wives accounted for nearly 90 percent of the total marriage immigrants, it showed.   

The third largest group of foreign nationals here was students who came to Korea to study. Among the total 93,232 international students, 20 percent were studying the Korean language, according to the statistics. Chinese again turned out to be the largest group among international students here with 72.9 percent, followed by Mongolians with 5.25 percent, Vietnamese with 3.47 percent, Japanese with 2.61 percent and Americans with 1.32 percent, the data showed. 

"The inflow of foreigners is expected to continue further on the back of the country's economic development and low birthrates,"

Kwak Jae-seok of Migration & Diaspora Research Institute said.

South Korea's birthrate, or the average number of children born to each woman in her lifetime, currently stands at around 1.23, much lower than the average birthrate of 1.71 tallied for members of the Organization for Economic Cooperation and Development.

"It is high time for South Koreans to strive to maximize the positive effects of a multicultural society and harmonize with foreigners living here," Kwak added.