A record high 63 percent of women aged between 15 and 64 held jobs in September, up 2 percentage points from a year earlier, according to a labor force survey by the Internal Affairs and Communications Ministry.

The rise reflects a growing number of companies hiring women as well as an increase in single working women amid the recent tendency to postpone marriage, it said, adding that an increase was particularly evident among women in their 30s.

However, the survey also showed that only about 40 percent of women continue working after the birth of their first child, indicating that efforts need to be made to provide support for families with children both at home and work.

Women are also being hired predominantly in part-time, nonregular positions. Upgrading their quality of employment is also a challenge for employers.

In September, the percentage of employees without full-time status came to 21.3 percent among working-age men, compared with 56.5 percent among women.

“The rate of women who continue their jobs after childbirth has not increased. The overall ratio of working women rose largely because of an increase of women who stay single or marry late,” said Shingo Ikeda, deputy chief researcher at the Japan Institute for Labor Policy and Training.

Long working hours and part-time status are among major reasons for many women to quit jobs after the birth of their first child, Ikeda said.

Women whose employment status is not full-time face a harder time taking child care leave because employers often encourage them to voluntarily resign or not renew their contracts once they become pregnant.

Meanwhile, women with full-time jobs often abandon or postpone returning to work after failing to find nursery schools for their children following child care leave, and this trend was observed especially in the metropolitan areas.

The government is aiming to tap female workers as a key driving force under its economic growth strategy at a time when the economy is expected to face labor shortages as a result of the aging population and the declining birthrate.

The employment rate of women aged 15 yo 64 has increased moderately over the past decade, up 6.2 percentage points compared with the 2003 average. The previous record high employment rate was 62.5 percent for women in this age group set in April. Data have been collected since 1968.

In the September report, among almost 39.2 million women in the 15-64 age group, just under 24.7 million were employed, according to the survey.

By age category, the employment rate was highest — 74.7 percent — among women aged 25 to 29, followed by those aged 45 to 49 (74.4 percent) and those aged 50 to 54 (71 percent).

The division among the age groups grew less sharp over a decade. The employment rate among women aged 30 to 34 rose 11.5 percentage points and that of those aged 35 to 39 rose 9.2 percentage points, due largely to the effect of the revised 2010 child care leave law requiring companies to introduce shorter working hours for those with children, the ministry said.

The climb in the female employment rate is also attributed to an increase in jobs available in the welfare and nursing care sector, where primarily women have been hired. The slow growth of salaries among their spouses is also seen as a factor encouraging women to take up jobs to supplement income.