Yeah, its a list from a tiny sample which is sort of the charm of it. There were only 2400 entries with up to 10 songs from Philadelphia area radio listeners that tune into a small, if much beloved station.
That's how you get things like "Angel from Montgomery" weighing in at 15. It's a perfectly good song, and I happened to have a Bonnie Raitt album with that song when I was at UConn more than 40 years ago, but number 15 all time ?
Also how you get things like
It ain't no use by New Orleans funk band The Meters. Back in the day it was played at that WXPN and enough people remember it to put it solidly in the middle of the pack at 1063. Don't think it would happen with a bigger sample.
Edit: Somehow I had forgotten that John Prine passed away this year, so the high ranking of Angel from Montgomery was a result of individual fans wanting to make sure he made the list. Apparently enough of them did to boost him all the way to 15. Another example of something that can happen with a small targeted sample that wouldn't happen if you took a survey of a couple of million.