South Korea's population is rapidly aging as people aged 65 or older account for nearly 16 percent of its population, government data showed Monday.

South Koreans in the age group stood at 8.13 million this year, or 15.7 percent of the country's population, according to the data from Statistics Korea.

The number of people aged 65 or older is expected to keep rising down the road to reach 10.51 million in 2025, or 20.3 percent of the total population, putting the country on the threshold of a super-aged society.

A country is defined as a super-aged society when at least 21 percent of its people are 65 or older.

Asia's fourth-largest economy became an aged society in 2017, when the proportion of those aged over 65 years reached over 14 percent of its entire population.

In 2060, the proportion is estimated to increase to as high as 43.9 percent.

All areas of South Korea, except for the central administrative city of Sejong, are estimated to become super-aged in 10 years.

In 2020, the number of people aged 65 or older is estimated to take up 14.8 percent of Sejong's population.

The data also showed cancer was the leading cause of death in South Korea last year, with some 751 per 100,000 people dying of cancer.

Cancer was followed by heart diseases (336 deaths), pneumonia (283), cerebrovascular diseases (232) and diabetes (87).

About half of those senior citizens have finished or are making preparations for old age, with 31 percent depending on the country's state pension program, according to the data. (Yonhap)