According to an NPD report released today, CD sales have continued to slip into oblivion, with iTunes accounting for 25% of the overall US music market – up from 21% in 2008 and 14% in 2007. The report indicates that while CDs are still the most popular format, claiming 65% of all music sold in the first half of 2009, digital music is quickly gaining ground.

Responsible for the remaining 35% of music sales, digital distribution is up from 20% in 2007 and 30% in 2008. Naturally Apple's iTunes is the dominant force here, holding 69% of the market - far more than any other service. AmazonMP3 for instance only accounted for 8% of the digital market.

Walmart took a handsome 14% slice of the entire market between downloads, their online store, and retail outlets. It was also the leader in CD sales, with a 20% share of that scene, followed by Best Buy at 16% and Target and Amazon tied at 10% each.