(Bloomberg) -- The oil industry just can’t seem to hold on to women workers.

That’s the conclusion of an industry survey presented at the World Petroleum Congress, a Houston event at which only 20% of speakers this week are women.

The share of women in the global oil and gas workforce was just 22% in 2020, exactly the same as in 2017, according to the study from Boston Consulting Group. The industry is recruiting more women, but they aren’t staying, Andrea Ostby, managing director and partner at the consulting firm, said Tuesday. The survey cited a number of career obstacles, including unfair evaluations and lack of training for women.

Other industries are achieving better gender diversity. The stagnation in oil indicates that “the talent war is on,” Ostby said. “People across industries understood how important diversity is for results.”

Businesses are increasingly interested in a more balanced ratio of men and women, because it has resulted in better financial outcomes. Companies with three or more female directors had a 53% higher return on equity than those with less, while companies with leadership teams with above average diversity saw an almost 10% improvement in earnings minus items, Ostby said.

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