Also, 506,000 couples, or 42.9 percent, were double-income families, and the percentage reached 50 percent for those who married less than one year ago.

Among 853,000 marriages that include salaried workers, 30.6 percent of them have a combined annual income of 30 to 50 million won, while 21.9 percent are in the basket of 50 to 70 million won, and 18.4 percent are in the 10 to 30 million won income group.

The findings reflect that an increasing number of South Korean people get married and have children when they are older, or give up on tying the knot and having babies altogether.

A separate survey showed that half of people thought that marriage is necessary in their lives last year, down from 56.8 percent polled in 2014.

The average age that a woman has her first child was 31.2 last year, up from 31 years in 2014. Some 23.9 percent of first-time moms were over 35 years of age.

The country's fertility rate, or the average number of babies that a woman is projected to have during her lifetime, has hovered around 1.2 since it dropped to a record low of 1.08 in 2005.

It reached 1.24 in 2015, marking the second-lowest fertility rate among members of the Organization for Economic Cooperation and Development, following Portugal with 1.23 based on available data compiled in 2014.

The average birthrate of OECD countries was 1.68 as of 2014. (Yonhap)