(CNN) People in South Korea are having fewer babies and that's a problem.

The country's total fertility rate last year fell to its lowest since records began, the government said on Wednesday.

The total fertility rate measures the average number of children a woman will have in her lifetime. In 2018, this dropped to 0.98 -- or less than one baby per woman, and a drop from the previous year's rate of 1.05.

This means 8.7% fewer babies were born in South Korea in 2018 compared to 2017.

According to the government report, which has been compiled annually since 1970, the fertility rate for women in their late 20s has fallen the sharpest.