By the end of 2006, there were 47 mln digital music households in the US (households with a member who downloaded, ripped, burned, played, or uploaded digital music). Among those households, 15 mln actively downloaded at least one music file from a P2P site in 2006 ? an 8% increase over 2005, but still a slower growth rate than was noted in prior years. While P2P user growth rates slowed, the average P2P user downloaded many more files in 2006 (5 bln files) than the previous year, which represents a 47% increase in P2P downloading compared to 2005 (3.4 bln files). While in 2005 NPD noted a two to one difference between the P2P and pay-to-download populations, in 2006 there were nearly 13 mln households using a paid digital music download services ? almost three times more than NPD reported in 2004. Overall, the number of music files purchased in 2006 exceeded 500 mln, which is a 56% increase from the previous year.