In most common occupations women still make less than men doing the same job for an equal amount of hours, according to new data released on Tuesday.
Overall they earn 77 cents for each dollar made annually by men and in some professions such as financial managers the number drops to 66 cents.
"These gender wage gaps are not about women choosing to work less than men - the analysis is comparing apples to apples, men and women who all work full time - and we see that across 40 common occupations, men nearly always earn more than women," said Ariane Hegewisch, a study director at the Institute for Women's Policy Research (IWPR), a non-profit research organization.
She added that the reasons are varied but discrimination law cases show that women are less likely to be selected for the best jobs, they get hired at a lower rate and don't get equivalent raises to men over the years.
"Discrimination in who gets hired for the best jobs hits all women but particularly black and Hispanic women," Hegewisch explained.
The findings, based on an analysis of earnings data for full-time workers from the U.S. Bureau of Labor Statistics, showed that in 2011 the median weekly wage for full-time female workers was $684, compared to $832 per week for men.
In the 20 most common occupations for women in every job, except bookkeeping and auditing clerks, women earned less, according to the report. The same held true for traditional occupations for men, apart from stock clerks and orders fillers.
More than twice as many women, 5.52 million, as men, 2.3 million, work in occupations paying poverty wages for a family of four, along with four out of 10 Hispanic women.
Three women's jobs -- cashiers, waitresses and maids -- and two men's occupations -- cooks and ground maintenance workers -- have salaries that put a family of four below the poverty.
"It is shocking that important occupations such as teaching assistants or nurses, psychiatric and home health aides, stressful and responsible jobs that are critical to the well being of our society, are likely to leave a woman unable to support her family even when she works full time and year round," said Dr. Heidi Hartmann, the president of the IWPR.
Hispanic women have the widest gender wage gap, according to the report. Their median weekly wage of $518, is 55 percent of what white men earn, compared to black women whose median earnings are $595, or 64 percent of a white man's wages.
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