When it comes to the number of women at the pinnacle of the business world, even meager growth can be meaningful. This year's Most Powerful Women list from Fortune magazine, released Thursday, illustrates that. The annual who's who of the top 50 female business leaders counts 27 CEOs on its ranking, up from 24 last year, making this the most CEOs since the list began in 1998.

As with any such ranking, there aren't too many surprises. (Unless you count Fortune's inclusion of an extra member, entertainment queen Taylor Swift at No. 51, a surprise.) Topping this year's list is General Motors CEO Mary Barra, who has won praise for her handling of GM's ignition-switch crisis, followed by PepsiCo's Indra Nooyi at No. 2. Last year's highest ranked woman, IBM CEO Ginni Rommetty, fell to No. 3 as Big Blue struggles with quarter after quarter of sales declines. Lockheed Martin CEO Marillyn Hewson and DuPont CEO Ellen Kullman round out the top five.

Last year, the same five women topped Fortune's ranking—which considers factors such as the size and importance of her business in the economy and the company's overall health—and only 11 of the women on the list this year have never been on it before. Among those new names are two women from Walmart (one of six companies with two women on the list), Judith McKenna and Michelle Gloeckler, as well as the new CEOs of Deloitte and KPMG U.S., Cathy Engelbert and Lynne Doughtie.

While the list may not be particularly surprising, it does remind us how far women have come in the corporate suite in a fairly short period of time. Just five years ago, for instance, there were only 12 CEOs of publicly traded companies on the list (plus one interim); other women held the title but only for a smaller firm or division within a larger company.

It also gives us a window into some potential female power players of the future. Two women who have been named as possible successors to JPMorgan CEO Jamie Dimon are on the list—CEO of asset management Mary Erdoes at No. 29 and CFO Marianne Lake at No. 31. So is Google and Alphabet CFO Ruth Porat, who moved west to Silicon Valley from Morgan Stanley earlier this year.

That this ranking gives us an idea of the names to watch is nothing new. In 2013, for instance, the list included an executive vice president of product development, purchasing and supply chain most people had never heard of—Mary Barra—who would go on to lead this country's largest car maker. And in 1998, a little-known telecommunications executive named Carly Fiorina topped the list in the ranking's first year. She is, of course, now running for president.

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