The proportion of young Japanese who are not married or dating has been on the rise over the past 20 years, according to  research on census data by a team at the University of Tokyo.

The proportion of single women has increased by 1.5 times, the report said, according to Oriental Weekly. Between 1992 and 2015, the percentage of women who were not in a relationship with the opposite sex increased from 27.4 percent to 40.7 percent, while that of men rose from 40.3 percent to 50.8 percent, the study said. 

In 2015, it found that 25.1 percent of men and 21.4 percent of women said they did not want to be in a relationship with the opposite sex, with relatively high rates among those with low incomes and without formal jobs.

An article headlined "Parasite singles': Why young Japanese aren't getting married" published last December by The Japan Times cited government data as showing that nearly a quarter of Japanese aged between 20 and 49 were single. 

Although many young people still constantly express their desire to marry, analysts say social and economic pressures are making tying the knot increasingly harder. 

For example, the social norm of single people staying with parents until they get married could contribute to a delay in entering marriage since they may think it is a "waste of time to have a relationship with someone who does not meet their conditions," Masahiro Yamada, sociology professor of Chuo University said, adding that the difficulty in acquiring affordable independent housing also contributes to people staying at their parents' home as long as possible.

Hypergamy, the preference of Japanese females to have men with more stable and higher-income jobs than their own, is also believed to be a reason. What's more, office environments traditionally used to meet partners, are now less relied on. 

Unstable economic conditions that create a fair share of unstable jobs also will not help people think about settling down but rather to worry not being sacked unexpectedly, according to Shuchiro Sekine, head of a trade union representing contract workers. Lower-income workers, even with a strong wish to get married, can still be held back by job insecurity.

A study issued by the government this year revealed that in 2017, around 60 percent of salaried men, compared to 22 percent of male contract workers, were married.