Tokyo, Japan (CNN) -- If more women worked, Japan could add millions of employees to its rapidly shrinking workforce, a government study released Tuesday said. The key is better pay and a more flexible work culture.
If women did not quit their jobs due to marriage or childbirth, the report says, Japan's workforce would increase by up to 4.5 million people. Female workers numbered 27.7 million in the Japanese workforce in 2009, compared to 38.4 million men.
The annual document analyzes the role of women in the Japanese economy and, this year, urges more flexibility so women can maintain careers and raise children.
There is a significant drop in the number of women working in their 30s, according to the report. Pay may be one of the reasons.
Total compensation for women equals about 40 percent of what men make in Japan, the government said. Hourly wages for women are about 70 percent of that for their male counterparts.
Although Japan has world's second largest economy, it also has the world's fastest aging population and one of the lowest birthrates on the planet. By 2050, the government estimates 40 percent of Japan's population will be over the age of 65.
The numbers represent a shrinking tax base for the Japanese economy -- one that has the world's largest debt to gross-domestic-product ratio, at nearly 200 percent. Paying that debt off will be an increasing challenge for Tokyo, if the number of taxpayers dwindles every year.