The number of people who are part of a nonfamily household topped one million for the first time last year.

According to the Korean Statistical Information Service(KOSIS) database of Statistics Korea on Monday, the number of nonfamily households in the nation surged nearly 12 percent on-year to a record 472-thousand-660 in 2021.

A "nonfamily household" refers to a residence consisting of no more than five people who are not related to each other. Living arrangements that fall under this classification include several friends living together or couples who are not legally married.

Such households topped 300-thousand in 2017, after standing in the 200-thousands in 2016. The figure then surpassed 400-thousand in 2020.

The number of people who are members of nonfamily households then exceeded one million last year, surging by a whopping 74 percent compared to 2016.

An official of the statistics agency said households of various forms are growing as more people live with others with whom they have no blood relation.

Some have voiced the need to revise laws and regulations in a manner that reflects such changes in what constitutes a household.