Women in the United States working full-time, year-round are paid 79 cents for every dollar paid to men, according to U.S. Census Bureau data.

The researchers looked at data from more than 22,000 working U.S. adults ages 30 to 65.

The findings illustrate a need for legislation to tackle the enduring U.S. pay gap, said co-author Katherine Keyes, an assistant professor at Columbia’s Mailman School of Public Health.

“Our findings suggest that policies must go beyond prohibiting overt gender discrimination like sexual harassment,” she said.

Such policies could include paid parental leave, affordable childcare and flexible work schedules, she said.

“What the U.S. really needs is a new law requiring employers … to compare the content of women’s and men’s jobs and develop a fair pay scale,” said Heidi Hartmann, president of the Institute for Women’s Policy Research in Washington, D.C.