Apple is still the No. 1 music retailer in the United States, but Amazon.com's online store is coming on strong.
More U.S. music buyers are getting their music fix through iTunes than from any other source, according to data released on Tuesday by NPD Group. Earlier this year, , and it maintained that lead during the six months from January to June, NPD said.
Wal-Mart is still in second place, followed by Best Buy. Taking fourth place from Target was Amazon, whose own music store has been growing in popularity, perhaps in part due to its .