Report: 5b songs illegally downloaded in US; only 509m legal downloads.

Five billion songs were downloaded from P2P networks in 2006 versus 509 million from legitimate online music stores like iTunes, according to NPD.

NPD also found that in 2006, the number of households with PCs that downloaded at least one song using free peer-to-peer software like LimeWire or BitTorrent, grew 7.2% to 14.9 million.

During 2006, the number of PC households that used legal online services increased 65.8% to 12.6 million.

However, the P2Pers download many more songs than legal downloaders--five billion to 509 million--a tenfold difference.

According to NPD analyst Russ Crupnick, one reason is that people have more room on their hard disks to store songs. "When I talk to people who are involved in a lot of peer-to-peer, they're running around with external hard drives," he said.

NPD gathered its data from tracking software installed on 12,000 home PCs. The data were adjusted to reflect the Internet-using population, and then extrapolated to the roughly 70 million Internet-using households in the US.