It could take women 47 years to reach parity with men as corporate officers at Fortune 500 companies, according to a new study.

The research, by Catalyst, an organization that works to expand work opportunities for women, found that women held just 15.6 percent of corporate officer positions at Fortune 500 companies, down from 16.4 percent in 2005.

Women are still more than twice as likely to hold staff positions, whereas men hold roughly an equal percentage of line and staff positions. Line position experience is important for advancement to the highest levels, the organization notes.