The number of female CEOs in Japan hit a record 649,262 this year, comprising more than 15% of all CEOs for the first time, according to a survey by credit research firm Tokyo Shoko Research.

The annual survey, released earlier this week, also showed that the number of female presidents among 4.25 million companies had increased threefold from 2010, when the figure was just above 210,000. The number of female CEOs, meanwhile, rose 37,038 from last year, or by 6%.

¡°The support of the central and local governments for (women) to start and succeed businesses as well as companies¡¯ efforts to improve working conditions for women are steadily increasing,¡± Tokyo Shoko Research said of the reasons behind the rise.

¡°But there is still deep-rooted prejudice based on gender roles. (For women) to juggle work with domestic affairs, child-rearing and nursing care, the help of men is indispensable,¡± the report said, calling for a change in people¡¯s mindsets at home and in the workplace.

Notable female CEOs of major companies include Japan Airlines President Mitsuko Tottori and Nomura Research Institute CEO Kaga Yanagisawa.

By prefecture, the number of female CEOs was highest in Tokyo (165,102), followed by Osaka (63,177) and Kanagawa (41,614). The lowest count was recorded in Tottori (1,697), the only prefecture where the number was below 2,000.

The share of female CEOs was the highest in Okinawa (20.62%), followed by Yamanashi (17.36%) and Tokyo (17.21%). Niigata (9.69%) had the lowest share.

The average age of female CEOs was 65.1 ¡ª 1.8 years older than their male counterparts.

It was most common for female CEOs to be in their 70s, with 25.8% belonging to that age group.

The companies of female CEOs were mostly small in terms of sales and employee numbers. Of companies with female CEOs, 69.8% had annual sales of less than ?100 million ($658,000), while 61.5% had less than five employees.

By industry, the service sector, which in the Tokyo Shoko Research survey includes restaurants and the cosmetics industry, had the highest number of female CEOs at 320,913, or 49.4% of the total. The highest share was in real estate, where 1 in 4 CEOs were female. Construction had the lowest share at 5.45%.

The most common given name among female CEOs was Kazuko for the 13th year in a row. The name was most popular from the early Showa Era (1926-1989) to 1952, which explains the high number of women with that name in senior roles today, Tokyo Shoko Research said.