Apple today announced that music fans have purchased and downloaded over 50 million songs from the iTunes Music Store, not including songs redeemed from the currently-running Pepsi iTunes promotion. The 50 millionth song, purchased last Thursday afternoon, was “The Path of Thorns” by Sarah McLachlan. Apple says iTunes users are now downloading 2.5 million songs per week, which is an annual run rate of 130 million songs per year.