One, this is just my favorites list, not every album I've listened to. And I've listened to my playlists on random quite a few times over the years.
Two, I don't listen to pop music, so the average is probably closer to 4-5 minutes per song. (About 362 hrs of music on the playlist, if you must know.)
Three, you can't just plug in a yearly rate, convert it to hours, and use it in any meaningful way.