Although women are increasingly responsible for the economic security of their families, they still earn significantly less than men, according to reports released on Tuesday, Equal Pay Day.

An annual report by the Institute for Women’s Policy Research (IWPR) found that full-time working women are paid only 77 cents for every dollar paid to full-time working men. In median weekly earnings, women earn only $684 per week, compared with $832 per week for men.

Yet almost 15 million households in the United States are headed by women, and 8.5 million of those households include children under the age of 18. Nearly 30 percent of households headed by women live below the poverty level.

"This new analysis illustrates just how much harm the wage gap does to women and families throughout the country, and especially to women of color where the gap between the wages paid to women and men is staggering," said National Partnership for Women President Debra L. Ness. "With state economies struggling and women increasingly serving as the sole or co-breadwinners for their families, tens of thousands of dollars in lost wages each year takes a tremendous toll."

An analysis by the National Partnership for Women found that the wage gape between men and women was smallest in the District of Columbia, Vermont, California and Nevada. It was largest in Wyoming, Louisiana, and Utah.

Women in the United States earn $10,784 less than their male counterparts. But the wage gape is even larger for African American and Latina women, who earn $19,575 and $23,873 less than men, respectively.

“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 these 40 common occupations, men nearly always earn more than women,” said Ariane Hegewisch, a Study Director at IWPR.

“Discrimination law cases provide us with some insights on the reasons that the wage gap persists: women are less likely to be hired into the most lucrative jobs, and -- when they work side by side with men -- they may get hired at a lower rate, and receive lower pay increases over the years," Hegewisch explained. "Discrimination in who gets hired for the best jobs hits all women but particularly black and Hispanic women.”

The wage gap has slowly been closing at a rate of less than half a cent per year since the Equal Pay Act passed in 1963, according to the National Partnership for Women. At that rate, the wage gap will completely close in more than 40 years.

[Modern business woman at office via Shutterstock]