HONG KONG — Marriages in China plummeted by a fifth last year, the biggest drop on record, despite manifold efforts by authorities to encourage young couples to wed and have children to increase the country’s declining population.

Declining interest in getting married and starting a family has long been blamed on the high cost of child care and education in China. On top of that, sputtering economic growth over the past few years has made it difficult for university graduates to find work and those that do have jobs feel insecure about their long-term prospects.

More than 6.1 million couples registered for marriage last year, down from 7.68 million a year earlier, figures from the Ministry of Civil Affairs showed.

“Unprecedented! Even in 2020, due to Covid 2019, marriages only decreased by 12.2%,” said Yi Fuxian, a demographer at the University of Wisconsin-Madison.

He noted that the number of marriages in China last year was less than half of the 13.47 million in 2013.

If this trend continues, “the Chinese government’s political and economic ambitions will be ruined by its demographic Achilles’ heel,” he added.

For Chinese authorities, raising interest in marriage and baby-making is a pressing concern.

China has the second-biggest population in the world at 1.4 billion — one that is aging quickly.

The birth rate fell for decades due to China’s 1980-2015 one-child policy and rapid urbanization. And in the coming decade, roughly 300 million Chinese — the equivalent of almost the entire U.S. population — are expected to enter retirement.

Measures taken last year by authorities to tackle the problem included urging China’s colleges and universities to provide “love education” to emphasize positive views on marriage, love, fertility and family.

In November, China’s state council, or cabinet, also told local governments to direct resources toward fixing China’s population crisis and spread respect for childbearing and marriages “at the right age.”

Last year saw a slight rise in births after a lull due to the pandemic and because 2024 was the Chinese zodiac year of the dragon — with children born that year considered likely to be ambitious and have great fortune.

But even with the increase in births, the country’s population fell for a third consecutive year.

The data also showed that more than 2.6 million couples filed for divorce last year, up 1.1% from 2023.