Katharine Graham, the former chairman and chief executive officer of The Post Co. and former publisher of The Washington Post, was the first woman elected to the Associated Press's board of directors. She's seen here with the board in New York in 1975. (Photo by Associated Press)

The White House is convening its United State of Women Summit on Tuesday morning to rally attention around gender equality issues. But when it comes to corporate boards of directors, the state of women isn't all that encouraging.

As part of the summit Tuesday, the nonprofit group Catalyst, which works to promote women in business and leadership, released its annual count of the women sitting at the boardroom tables of America's biggest companies. It found that in 2015, 19.9 percent of these powerful positions leading companies in the S&P 500 index were female, up marginally from the 19.2 percent of female directors the year before. Women held less than 10 percent of top-earner positions. And just over a quarter of new board members were women, meaning the potential for gender equality on boards -- or even numbers approaching parity -- remains far off.

"That means almost three-quarters [of seats] are now filled by men," said Brande Stellings, vice president of corporate board services for Catalyst. "That's a lot of missed opportunities to change the status quo."

Yet there is a small piece of good news. Catalyst's data also showed that last year, just 2.8 percent of S&P 500 companies, or 14, had no women on the board. But because Catalyst pulled data from the board makeup at each company's 2015 annual meeting, those numbers have improved. In August, after many of those annual meetings took place, The Post had S&P Global Market Intelligence run the number of S&P 500 companies with no women on the board, and it found just 12. We had them run the numbers again this week, and there now appear to be eight in that group of large companies.

Stellings agreed that was good to hear, but tempered her enthusiasm. "We have tried to look for bright spots," she said. "There are fewer and fewer companies with zero board members -- but it’s pretty sad that that’s where the floor is."

Kevin Kelly, director of publications for S&P Global Market Intelligence, notes that their data does not include gender as reported by companies, but he conducted a keyword search of director biographies in the database. We checked their list against company web sites. Currently, the eight companies are:

At least one company on the list wouldn't have been just months ago. Last year, Delphi appointed Ixia CEO Bethany Mayer to its board, but she resigned in April due to personal and professional reasons, a spokesperson said in an email. "Diversity is a core value at Delphi and we are committed to a diverse board of directors as we search for a suitable candidate to replace Ms. Mayer," the spokesperson said.

A spokesperson for Discovery shared an emailed statement from its chairman, Bob Miron, saying that "we are engaged in a robust process to identify diverse board candidates, and we continue to develop a slate of diverse candidates that will best meet our board's needs." The company has faced recent scrutiny from shareholders over its all-white, all-male board.

A Qorvo spokesman pointed to a recently adopted resolution by the board to "take meaningful steps" to add one or more women to the nominees at its next annual meeting. Other companies did not immediately respond to a request for comment.

Yet even as there are fewer companies without female directors, one-quarter of companies in the S&P 500 have only one female director, according to Catalyst's report. Stellings said it published that statistic because "we want to make sure one doesn't become the new zero," she said. "Is one woman on a board really satisfactory progress? We’d say no, and have some concern companies feel like [they add] one and done -- they've done their duty."

That's in part because research has shown that adding one woman to the board, or even just two, can leave women with "token" status, and the diverse viewpoints they bring to the group don't have much of an impact until they reach a "critical mass" of three or more.

"When there’s fewer of a group -- in this case women -- your view becomes much less salient," Stellings said. "You're speaking as a woman rather than all the other expertise and background you can bring." 

Catalyst's report finds that just 14 percent of companies had women filling 30 percent or more seats. Only a small number of companies have reached gender parity on their boards, with equal numbers of men or women.

Last week, Etsy's stockholders elected another woman to its board, bringing its numbers to three men and three women, one of the few publicly traded companies to reach gender parity. General Motors is another, with six men and six women on its board. A few companies that actually have more women than men on the board are American Water WorksNavient Solutions and TEGNA.

Read also:

Only one woman was named CEO of a major company in North America in 2015

A big reason the old, white boys’ club image is so hard for corporate boardrooms to shake

Like On Leadership? Follow us on Facebook and Twitter, and subscribe to our podcast on iTunes.