America’s relationship to gun violence onscreen is a complicated one — but it’s only getting more prevalent. A new study by the Annenberg Public Policy Center and Ohio State University has found that the amount of gun violence in the top-grossing PG-13 movies has more than tripled since 1985, and in 2012 it exceeded the gun violence in the top-grossing R-rated movies.

The study, “Gun Violence Trends in Movies,” also shows that the overall rate of violence in the biggest box-office movies has more than doubled since 1950, and that in 1985, the first full year of the PG-13 rating, the amount of gun violence in popular PG-13 movies was similar to that in movies rated G and PG. Since 2009 it has rivaled the level of gun violence in R-rated movies.

“It’s disturbing that PG-13 movies are filled with so much gun violence,” Dan Romer, director of the Adolescent Communication Institute of the Annenberg Public Policy Center and a co-author of the study, said in a press release. “We know that movies teach children how adults behave, and they make gun use appear exciting and attractive.”

Critics of the MPAA’s rating system have long said that what makes a movie rated the studio-happy PG-13 is somewhat vague. On the MPAA’s website they state, “There may be depictions of violence in a PG-13 movie, but generally not both realistic and extreme or persistent violence.” Interestingly, this study found that the number of movie scripts containing segments with gun violence has not generally changed since 1985 in G-, PG-, and R-rated movies. But it grew considerably in PG-13 movies, which the study notes make up more than half of the revenue from the top-grossing movies.

“It may be time to rethink how violence is treated in movie ratings. We treat sex as R,” Romer continued. “We should treat extreme gun violence as R.”

A rep for the MPAA declined to comment on the study.