Hollywood often catches flack for its lack of diversity and this recently published study shows why.

The University of Southern California's Annenberg School for Communication and Journalism reveals that the film industry's diversity epidemic is as bad as ever, with the number of roles for women, minorities, and LGBT characters remaining stagnant for more than seven years.

The research, titled 'Inequality in 700 Popular Films: Examining Portrayals of Gender, Race, and LGBT Status from 2007 to 2014, examined the top 100 grossing films from each year. Everything from the cast, crew, to screenplay was analyzed.

In an interview with Deadline, project leader Professor Stacy L. Smith said:

"Rarely do you have a report that measures every speaking character on screen. Here's a picture of what we see happening across the entire landscape. I don't think we're seeing a great deal of change. I call it 'an epidemic of invisibility.'

The results show a stunning lack of progress. Here are some key figures gathered by The Hollywood Reporter:

Only 30.2% of characters across all 700 movies were female

• Of the 21 female leads or co-leads in 2014, only three were of color. None were over the age of 45.
• In 2014, 12.5% of characters were black, 5.3% were Asian and 4.9% were Latino. These proportions have remained statistically consistent every year since 2007.
• More than 40 of 2014's top 100 grossing movies had no speaking characters of Asian descent. There were no black speaking characters in 17 movies.
• 3.5% of the American population now identifies as LGBT, but just 0.4% of 2014's movie characters were gay, lesbian or bisexual. There were no transgender characters.

Behind the camera, representation has stayed equally dismal. Of the 779 credited directors of the 700 most popular movies since 2007:

• 28 were women, 45 were black and 19 were Asian
• Last year's crop of directors featured just two women and four African Americans. Only one (Ava DuVernay) was both.