> Eb with 3 flats, for instance, is slightly (though not statistically significantly) more common than F with only 1 flat.
Ask any singer: F is the hardest key to sing in. Most people who have to sing in F unaccompanied will inevitably go flat over the course of the song without lots of practice.
I would have plotted the frequency of each chord relative to the key. (e.g., count chords as I/IV/V/ii/etc. instead of C/F/G/Dm) This automatically corrects for the relative popularity of different keys seen earlier in the post.
Ask any singer: F is the hardest key to sing in. Most people who have to sing in F unaccompanied will inevitably go flat over the course of the song without lots of practice.
I would have plotted the frequency of each chord relative to the key. (e.g., count chords as I/IV/V/ii/etc. instead of C/F/G/Dm) This automatically corrects for the relative popularity of different keys seen earlier in the post.