2007 saw a sharp increase in the amount of music acquired for free via peer-to-peer (P2P) downloading, according to NPD's annual survey of Internet users in the US.

Overall CD sales plummeted from 41% to 32% while peer-to-peer file sharing grew from 14% to 19% by volume.

The amount of music that was acquired by being "Burned from others" or "Ripped from others" was also 19%.

The survey also shows that more people paid for digital downloads in 2007, with that market growing from 7% to 10%

Russ Crupnick, head of NPD's music service told The New York Times that: "The number of people who do peer to peer in 2007 versus 2006 has been stable… The number of files taken per users has increased significantly."

The Guardian’s Jack Schofield suggests that this is “because of the shift of many users from Limewire to BitTorrent, which makes it easier to download whole albums.”

The survey also showed that most still listen to music via the radio, followed by playing CDs and, thirdly, listening in to music on a computer. It also confirmed that Amazon's DRM-free music service has a much older, more male-oriented audience who tend to buy more full-length albums when compared with Apple's iTunes