Apple announced that iTunes is now the number two music retailer in the US, behind only Wal-Mart, based on the latest data from the NPD Group and that iTunes now has 50 million 
customers. The store has sold over four billion songs with 20 million songs sold on Christmas Day 2007 alone.
The #2 claim is based on data from market research firm the NPD Group’s MusicWatch survey that captures only sales that consumers reported in the past week unit and counts one CD representing 12 tracks excluding wireless transactions. According to NPD, The iTunes Music Store became the second-largest music retailer in the US after Wal-Mart based on the amount of music sold during 2007 according to this measurement. SoundScan which measures actual sales continues to rank Amazon above iTunes.
