The number of babies born in Japan last year fell for an eighth straight year to a new low, government data showed Tuesday, and a top official said it was critical for the country to reverse the trend in the coming half-dozen years.

The 758,631 babies born in Japan in 2023 were a 5.1% decline from the previous year, according to the Health and Welfare Ministry. It was the lowest number of births since Japan started compiling the statistics in 1899.

The number of marriages fell by 5.9% to 489,281 couples, falling below a half-million for the first time in 90 years — one of the key reasons for the declining births. Out-of-wedlock births are rare in Japan because of family values based on a paternalistic tradition.

Surveys show that many younger Japanese balk at marrying or having families, discouraged by bleak job prospects, the high cost of living that rises at a faster pace than salaries and corporate cultures that are not compatible with having both parents work. Crying babies and children playing outside are increasingly considered a nuisance, and many young parents say they often feel isolated.

Chief Cabinet Secretary Yoshimasa Hayashi told reporters Tuesday that the ongoing declining birth rate is at "critical state."

"The period over the next six years or so until 2030s, when the younger population will start declining rapidly, will be the last chance we may be able to reverse the trend," he said. "There is no time to waste."

Prime Minister Fumio Kishida has called the low births "the biggest crisis Japan faces," and put forward a package of measures that have included more support and subsidies mostly for childbirth, children and their families.

But experts say they doubt whether the government's efforts will be effective because so far they have largely focused on people who already are married or already are planning to have children, while not adequately addressing a growing population of young people who are reluctant to go that far.

The number of births has been falling since 50 years ago, when it peaked at about 2.1 million. The decline to an annual number below 760,000 has happened faster than earlier projections predicting that would happen by 2035.

Japan's population of more than 125 million is projected to fall by about 30% to 87 million by 2070, with four out of every 10 people at age 65 or older. A shrinking and aging population has big implications for the economy and for national security as the country seeks to fortify its military to counter China's increasingly assertive territorial ambitions.