Queen is the first classic artist to topped the 2 million in iTunes digital sales. Only eleven songs that were released prior to the opening of the iTunes store in April 2003 have topped 2 million. Awesome!!
In chronological order, they are:
1) Bohemian Rhapsody
2) We Will Rock You
3) Don't Stop Believin
4) Eye Of The Tiger
5) Billie Jean
etc.. link