The numbers are stunning: From 2007 to 2014, women made up only 30.2 percent of all speaking or named characters in the 100 top-grossing fictional films released in the United States. That’s bad enough to repeat: For every 2.3 male characters who say “Dude,” there is just one woman saying “Hello?!”

That is one of the findings in a study, “Inequality in 700 Popular Films,” being released Wednesday, that looks at gender, race, ethnicity and what one of the report’s researchers, Stacy L. Smith, describes as an “epidemic” when it comes to diverse representation. The report was produced by the Media, Diversity & Social Change Initiative at the University of Southern California’s Annenberg School for Communication and Journalism.

The report is crammed with numbers that show the extent of this misrepresentation when movies like “Captain America: The Winter Soldier” hit screens:

— The movies are white: 73.1 percent of all the speaking or named characters in the top 100 movies were white.

— The movies are straight: Only 19 total characters were lesbian, gay or bisexual — none were transgender.

— The movies are young: Only 19.9 percent of female characters were 40 to 64 years old.

— The movies are male: Only 1.9 percent of the movies were directed by women.

Even many casual observers may now be aware of the hurdles facing female directors, particularly when they try to storm the big studios. Yet those problems, as this latest study confirms, are simply part of a far larger picture. In 2014, not a single title in the top-grossing 100 fictional films starred a woman over 45. One reason is that Meryl Streep, the hardest-working woman in cinema, had only supporting roles, including in the Disney musical “Into the Woods.” That fractured fairy tale at least featured several women in pivotal roles, which isn’t the case in most movies, family friendly or not. According to the “Inequality” report, for 2014 “girls/women make up less than a third of all speaking characters on screen and less than a quarter of the leads/co-leads driving the story lines.” For instance, that year women made up only 21.8 percent of the speaking or named characters in action and adventure movies, where male superheroes and all manner of other bros dominate.

A lot of the information in the report isn’t new, even if it remains newsworthy. Among other things, the findings are a blunt reminder that female-driven blockbusters like “The Hunger Games” and African-American dramas like “Selma” remain exceptions in a largely homogeneous field. Art may be a mirror of life, but it is often a badly distorted one in mainstream American cinema. And, while women may be about half of the population — and for years have bought half the movie tickets — they remain a persistent on-screen minority. The same is true of certain races and ethnicities. The report found that 4.9 percent of all speaking or named characters in the 100 top-grossing movies of 2014 were “Hispanic/Latino.” As the report pointed out, this low number is at odds with off-screen demographics: Latinos were 17.1 percent of the population (in 2013). And in 2014 they were also 25 percent of what the industry calls frequent moviegoers.

The “Inequality” report comes at a time of increasing criticism about the industry’s on-screen and off-screen practices, giving further empirical support to what has become a steady stream of righteous complaint. In May, the American Civil Liberties Union — citing “the widespread exclusion of women directors from employment in directing episodic television and feature films” — sent letters to state and federal agencies seeking an investigation of the hiring practices of the major Hollywood studios, networks and talent agencies. That same month, Sen. Barbara Boxer, Democrat of California, and four other female senators, sent a letter to the major studios asking them to respond to an earlier Annenberg/U.S.C. study that found that only 4.1 percent of top-grossing films over the last decade had female directors.

Lena Headey in “300: Rise of an Empire.”

Warner Bros. Pictures

The “Inequality” report is part of a growing wealth of data about the industry’s practices that are, study by study, making the case for change. Dr. Smith also helped write that earlier study and was one of the principal researchers — along with Marc Choueiti and Katherine Pieper — on a widely publicized multiyear study done with the Sundance Institute and Women in Film on the crisis facing female directors. For the “Inequality” study, they were joined by a team that swelled to an estimated 70 to 80 people; most of the team members are undergraduate students. Dr. Smith said on Friday that it was one of her students who had inspired her to start looking at the representation of lesbian, gay, bisexual and transgender characters, which is in keeping with studies that show that young Americans tend to be liberal in their political and social views. (She declined to name the student, citing privacy concerns.)

Scarlett Johansson in “Captain America: The Winter Soldier.”

Marvel Studios and Walt Disney Pictures

As that outspoken student suggests, moviegoers are doing their activist part, as exemplified by Every Single Word, a Tumblr by Dylan Marron that uses videos to underline the (often few) words spoken by nonwhite movie characters. What Every Single Word underscores is that the roles often available to nonwhite performers — think of the ubiquitous black friend, the Latina waitress and the Asian storekeeper — are often little more than casting tokenism. The point isn’t that the mainstream studios are deliberately racist or sexist. As Mr. Marron said in an interview last month in The Washington Post: “I’m not saying that any of these films are racist. I’m not saying that any of these filmmakers are racist. I’m saying that the system that they’re contributing has some deeply racist practices.”

The question now for anyone who loves movies is obvious: What next?