According to the report, the number of those aged from 9 to 24 dropped to 9.8 million last year from just over 10 million in 2012. The youth population last year accounted for 19.5 percent of the total population in Korea.
The ministry predicts that young people will only account for 11.4 percent of the total population by the year 2060. In 1978, they made up 36.9 percent.
Meanwhile, the number of adolescents from multicultural families has been on the rise. The population increased by 18.8 percent from 46,954 in 2012 to 55,780 in 2013.
Last year, they made up 0.9 percent of their age group in Korea. In 2009, they accounted for 0.3 percent.
The report also found that more than 25 percent of children from multicultural families resided in Gyeonggi Province last year, mostly in Ansan, Bucheon and Suwon.