According to the number crunchers at NPD Group, the trend that came to a head last year when Apple beat out Wal-Mart for the title of largest Stateside music retailer is continuing apace. That's right -- one in four songs sold in America is sold on iTunes, while Wal-Mart (including CD sales through retail stores, sales through their website, and Wal-Mart Music Downloads) holds the number two position at 14 percent. And number three, if you're morbidly curious, is Best Buy. In addition, 69% of all digital music sold in the US comes from the iTunes store, with Amazon ranking second at 8 percent. When talking formats, the CD remains the most popular at 65 percent, but as some dude named Russ Crupnick (NPD's vice president of entertainment industry analysis) notes, "with digital music sales growing at 15 to 20 percent, and CDs falling by an equal proportion, digital music sales will nearly equal CD sales by the end of 2010." Which can only be a good thing, if it means that we'll never have to step into a Wal-Mart again. Sales of ringtones and sales to consumers under 13 were not tabulated, which means the data may incorrectly skew away from purchases of The Wiggles' Go Bananas! and that Crazy Frog song.

[Via TUAW]