The rule in music sales is not 80/20 but rather 91/2.1

The 80/20 rule applied to the music business would translate as 80% of the music sold comes from 20% of the artists. In 2009 it played out to be 91/2.1: 91% of the music sold came from 2.1% of the artists. that's a harsh reality check for do-it-yourselfers.