Nearly half of couples remain childless in the first 5 years of marriage in South Korea, government data showed Tuesday.

According to the Statistics Korea, the number of newlywed couples, defined as those married for 5 years or less, stood at at 974,000 in 2023, marking a 5.6 percent decrease from 1.03 million in 2022. This is the first time the figure has fallen below 1 million since the government began tracking such data in 2015.

The number of newlywed couples has been on a steady decline since 2015, when it stood at 1.47 million. The figure has since dropped by about 50,000 to 80,000 annually, highlighting a sharp decline in marriages rates.

Among such couples, first marriages accounted for 78.9 percent. The proportion of these couples who didn't have children reached 47.5 percent last year, a 1.1 percentage point increase from the previous year.

The data also showed that double-income couples were less likely to have children, compared to single-income couples. Only 49.6 percent of dual-income newlyweds had children, compared to 57.4 percent of single-income couples -- a gap of 7.8 percentage points.

The average annual income of first-married newlywed couples was 72.65 million won ($50,779), a 7 percent increase from 67.9 million won in the previous year. Among them, dual-income couples earned an average of 89.72 million won, while single-income couples earned 53.69 million won.