The fourth annual Women in the Workplace survey from LeanIn.Org and McKinsey & Co., released this week, reveals that U.S. companies have "made almost no progress improving women's representation," at any level, since the study was first conducted in 2015.

This year, 279 companies representing 13 million employees shared data for the study, and 64,000 employees were surveyed about their experiences.

The report found that the gap between men and women starts early: 54 percent of entry-level jobs go to men. Then for every 100 men promoted to manager, only 79 women are promoted. The gap widens further in the C-suite, where about one in five leaders is a woman, and one in 25 is a woman of color.

The study arrives in a year when the number of female CEOs of Fortune 500 companies declined 25 percent from the previous year.

"Women get less support from managers — and that's getting credit for their ideas, getting help managing organizational politics, getting celebrated for their accomplishments," says Rachel Thomas, president of LeanIn.Org, the nonprofit founded by Facebook COO Sheryl Sandberg to support women in the workplace. "Women are disadvantaged out of the gate, and they do not catch up."

Most companies today have anti-harassment policies, but the survey also found more than a third of female employees, and more than half of senior-level women, have experienced sexual harassment during their careers.

There has been some progress, though. The study found that an increasing number of women are asking for promotions and pay raises. The report recommends that companies set goals, report progress and reward success in hiring practices. It also suggests making senior leaders agents of change.

California recently became the first state to require women on corporate boards. Depending on their size, some companies will be required to include multiple women on their boards by 2021. Thomas says the legislation could help move the needle, particularly if it pushes companies to appoint more than one woman director.

"What I'm really encouraged to see is they plan on over time making sure there's multiple women on boards, not just one," says Thomas. "We know from our research that if you are one of the only women in the room, or the only woman in the room, you are having a markedly worse experience in the workplace, and that of course is the same on corporate boards."

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