The government's goal of boosting the ratio of women in leadership positions in every field to 30 percent by 2020 is looking increasingly unrealistic, the 2015 White Paper on Gender Equality released Friday shows.

The white paper, compiled by the Cabinet Office and approved by the Cabinet the same day, reveals that the percentage of female leaders in various fields — defined as lawmakers, highly skilled professionals or corporate department heads and higher — remains much lower than the 30 percent target.

Japan has long been among the world's worst performers in terms of gender equality, ranking 104th out of 142 countries covered by the World Economic Forum's gender gap index in 2014.