Of the CEOs who lead the companies that make up the 2018 Fortune 500 list, out today, just 24 are women.
That number is down 25 percent from last year's record-breaking 32 female CEOs, the highest share of women since the Fortune's first 500 list in 1955. While women were at the helm of 6.4 percent of the companies on 2017's list, that number is now down to 4.8 percent.
The biggest reason for this drop, according to Fortune, is that more than a third of Fortune 500 female CEOs resigned in the past year. That includes several 500 veterans, like Campbell Soup Co.'s Denise Morrison, Hewlett Packard's Meg Whitman, Mondelez's Irene Rosenfeld and Avon's Sheri McCoy.