According to recent NPD data, Apple's iTunes has become the third largest Music retailer in the United States, for both online and physical format sales combined.

NPD Group MusicWatch has just published the study (via CNET) and shows the following market shares for the music retailers top five:

1. Wal-Mart - 15.8%
2. Best Buy - 13.8%
3. Apple iTunes - 9.8%
4. Amazon - 6.7%
5. Target - 6.6%

In a previous study published in January, the comany was fourth, behind Wal-Mart, Best Buy and Target. Jobs had mentioned this study during the MacWorld Expo opening keynote and dropped "guess who's our next Target", refering to the third largest music retailer at that time.

Amazon has since entered the scene in online music sales, it used to sell music in physical formats only, but the entrance in the online music market didn't help the online retailer to gain much market share overall.