Dood, they also have Pink Floyd as one of the top acts in Iran!! And Afghanistan is all about The Red Hot Chilli Peppers? I am not so sure.....the list for maine seems like its pretty accurate, but i am a bit unsure for some other stuff.
I'm going to go ahead and guess that the data is from major labels, not independant or indie Iranian music. I doubt there are any big labels in Iran that are reporting to Gracenote.
So, sure.. it isn't necessarily a very good indicator of true listening habits. Nevertheless, it is interesting to see what sells for the big con-gloms (hmm, I like that. I may start using the term con-glom more often).
The take away here is that the big bread winners are still a very small group of tried-and-true acts like the Beatles.
Statistics of note: Brits comprise 50% of the list, and the only two females on the list are also the only two that started their careers after the Berlin wall came down.