The government will no longer use the term "lifelong singles" as a label for people who have not married by age 50, deeming the term inaccurate as Japanese are increasingly tying the knot later in life, officials said Thursday.

The label has been used in annual white papers and statistics on the grounds that the fertility rate of women falls significantly when they enter their 50s.

But its use, which is believed to have begun some 30 years ago, has been criticized due to it implying that marriage and parenthood are inextricably linked and because it suggests people do not marry after 50.

The government has already removed the descriptor from some white papers in response to the evolving definition of the family. However, the percentage of "lifelong singles" will continue to be included in demographic forecasts and other statistics as it serves as a key indicator, with the data categorized simply as referring to "people unmarried by 50," they said.

The data on the percentage of singles at age 50 is released by a health ministry research institute in conjunction with the national population census conducted every five years. The data does not include those who divorced or were made single by the death of a spouse.

In 1985, under 5 percent of men and women were classed as unmarried before 50, but the figure eclipsed 10 percent for men in 2000 and rose above 20 percent for men and 10 percent for women in 2010.

In 2015, the proportion of people who had not married by age 50 hit a record 23.37 percent for men, or around one in every four men, and a record 14.06 percent for women, or one in every seven women, according to the National Institute of Population and Social Security Research.

Meanwhile, the country's average marriage age has continued to rise, standing at 31.1 for men and 29.4 for women in 2015.

An official at major Japanese matchmaking agency Zwei Co., believes the idea that marriage is something for young people is becoming outdated, adding the agency sees more than 300 registered members marry at 50 or older every year.

Among Zwei's membership as of February, 24.5 percent are men in their 50s and 11.2 percent are women of the same age group, and nearly 80 percent have never married, according to the company.

Experts have attributed the rising trend in the rate of unmarried people at 50 to the lack of social pressure to wed and the increasing prevalence of people employed on a temporary basis, leaving them concerned that they are unable to support a family.

The institute estimates the number of people unmarried at 50 will continue to trend upward, reaching about 29 percent for men and 19 percent for women in 2035.

Against the backdrop of more couples choosing to forgo having children and people forming nontraditional families, the government has been gradually phasing out the use of the term "ratio of lifelong singles" in recent years.

Since its 2017 edition, the white paper on labor and welfare has started instead using the category "the proportion of people who are unmarried by age 50," while the Cabinet Office's 2018 white paper on falling birthrate countermeasures inserted a footnote saying it is "sometimes referred to as ratio of lifelong singles."

To avoid confusion, officials said the government may use both "lifelong singles" and "people unmarried by 50" in the meantime.