Data taken from here and supplemented by Wikipedia and Box Office Mojo.
Starting with 1913 because I guess it's really hard to get data from earlier years.
To get a sense of how "good" the most successful films are throughout the years, here are the average ratings of the films for each decade:
1910s - 2.97
1920s - 3.20
1930s - 3.74
1940s - 3.31
1950s - 3.71
1960s - 3.91
1970s - 3.99
1980s - 3.86
1990s - 3.87
2000s - 3.92
2010s - 3.67
2020s - 3.40
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Status: Updated through 2025
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My "Random Topics" series:
Clever Girl/Boy
Films where Richard Gere plays a lawyer from Chicago
Films where Seth Green is cared for by a large…