“But how can you figure that out?!” you shout at whatever device you’re reading this on. “Film is too subjective an art form for you to make overarching statements like that!”
That’s a very good point, but you’re overlooking two things: 1) the Oscar best picture nominations, and 2) film ratings on the Internet Movie Database. Both obviously have degrees of subjectivity, but that’s levelled off somewhat with each institution’s sheer number of voters or raters.
So, to work out what year was the best ever for cinema, we’ve taken all the films nominated for each year’s Best Picture Oscar, and then worked out their average IMDb rating. I’ll just point out that these were the ratings as of the week of the 88th Academy Awards on 22nd February