Only 8% of Hollywood’s top films in 2018 were directed by women, down from 11% the prior year, despite high-profile efforts to improve gender equality, a study released on Thursday showed.

The percentage is roughly unchanged from two decades ago, according to the annual study, which found a “radical underrepresentation” of women in the industry.

“The study provides no evidence that the mainstream film industry has experienced the profound positive shift predicted by so many industry observers over the last year,” study author Martha Lauzen, executive director of San Diego State University’s Centre for the Study of Women in Television and Film, said in a statement.

The centre has been producing the “Celluloid Ceiling” report for 21 years.

Allegations of sexual harassment in Hollywood became public in late 2017, prompting calls for more women at all levels of the entertainment business.

Yet in 2018, women accounted for just 8% of directors of the 250 highest-grossing Hollywood films, less than the 9% in 1998.