The early state pension program was introduced to guarantee income for senior citizens up to five years earlier than norm.

Instead of the regular pension program, those applying for the early program can receive benefits from age 55, although this entails a reduction in pension benefits by 6 percent annually.

The NPS attributed the decrease to South Korea becoming an aged society and more people are choosing to get a steady income as late as possible.

South Korea's share of senior citizens reached 13.1 percent of the country's population of 50.62 million in 2015. A country is defined as an "aged society" if more than 14 percent of the population are 65 or older. (Yonhap)