The Huffington Post featured an op-ed from USC Annenberg Professor Stacy Smith on her latest study that showed that the number of women in popular films over the last five years has remained around 30 percent.

Last year, the number dropped to 28 percent, the lowest in five years. The study also found that the age of female characters is much lower than that of male characters. The percentage of female characters over 40 has remained around 23 percent for years covered by the study.

“Perhaps this is good news for aspiring female actors in their 20s, but it confirms the notion that women ‘of a certain age’ have a sell-by date when it comes to the big screen,” said Smith.

Hypersexualization of teenage female characters is also on the rise.

In the last five years, partial nudity of teenage females in popular film has gone from 23.3 percent to 55.8 percent. There is also a correlation between the gender of writers, directors and actors. Female directors and writers have been proven to feature more females in their films and sexualize those female characters less than male directors and writers.

According to Smith, “the simplest solution is to populate mediated worlds to match the world we live in – a world where half the people on the street, in the hospital, at the coffee shop, and in the theater are females.”

Marc Choueiti and Katherine Pieper also worked on the study.