Together, those in their 40s or 50s accounted for 33.4 percent of all people here. Out of all voters or people aged 19 years or older, those in their 40s or 50s accounted for about 40 percent of the total.

People in their 30s came to about 7.51 million or 14.5 percent of the overall population as of end-February, with those in their 20s reaching 6.74 million or 13 percent of the total.

The report from the Ministry of the Interior partly offers a view on which age groups the country's political parties must focus on to win the May 9 presidential election.

For nearly three decades since 1987, presidential elections have been held in December. The next election was again set to be held in December this year, but has been moved up to May after former President Park Geun-hye was dismissed by a Constitutional Court ruling on March 10, leaving the top executive post vacant.

By region, people in their 40s made up the single largest age group in nine major cities and provinces throughout the nation, including Seoul, while those in their 50s made up the largest age group in seven areas, including the second largest city of Busan and Gangwon Province.

Meanwhile, the monthly demographics report also showed a continued acceleration in the aging of the population. As of end-February, people aged 65 years or older came to 13.7 percent of the total, up 0.2 percentage point from 13.5 percent at the end of 2016.

The proportion of people aged 15 years or less, on the other hand, further slipped to 13.3 percent from 13.4 percent over the cited period, according to the report. (Yonhap)