@hamburger_helper said:

It would be cool if these numbers could be normalized by the sample size - ie cover songs are a huge percent, but how does the number of covers played divided by the number of songs in that pool compare to something like the number of songs from the siket disk played divided by the number of songs on the siket disk... I would be curious to see those numbers, I think it would be a somewhat more accurate representation about popularity and trending.

So, I think this is what you were getting at. It does normalize things, to some extent.

One point made by @Just_Ivy as I was putting this together was that, if you look at any album for a year or two after it first comes out, it will probably have a spike in plays, then level off. Hence the gigantic lead for Joy.

This graph plots number of total plays for each album divided by number of songs for each.