The ratio of firstborns in the country's births exceeded 60 percent for the first time last year.
According to Statistics Korea on Sunday, among the babies born last year, 156-thousand were firstborns, accounting for 62-point-seven percent of all births.
That is the highest since the country started compiling related data in 1981, surpassing the previous record of 56-point-eight percent set in 2021.
The number of firstborns increased by about eight-thousand in 2022 from a year earlier, the first increase since 2015 when it rose by three-thousand.
Meanwhile, the number of secondborns dropped from 91-thousand in 2021 to 76-thousand in 2022, while the number of children who are not first- or secondborns slipped by four-thousand to 17-thousand during the period.
Last year, the total number of births decreased by 12-thouand or four-point-four percent on-year.
The percentage of firstborn babies has been on the rise for 12 consecutive years since 2011, while the share of secondborns has been steadily declining since 2015.