On July 1st, 1984, the Motion Picture Association of America (MPAA) introduced the PG-13 rating, providing a classification between PG and R. Now, almost 30 years later, PG-13 movies have become the second most common at US box offices after R-rated films. However, due to their widespread appeal among adolescents and adults, PG-13 movies now generate more gross revenue at US box offices than all other movies combined.

Some readers may be curious about the average gross revenue per movie by rating. I have chosen not to graph this as I believe it to be misleading (and remarkably noisy). The gross revenue for films is nowhere near a normal distribution – each year, there are usually a few megahits at the box office while the vast majority fizzle by comparison. So the medians are all low, but the averages are artificially high due to a few extreme outliers. Consequently, it will have to suffice to say that the rise of the PG-13 rating is due both to the number and popularity of the movies.

Data source: http://www.boxofficemojo.com/yearly/