According to NPD, 36 million US consumers paid for digital music last year, 8 million more than 2007. Apparently there were 17 million fewer CD buyers in 2008 than 2007. Overall, they claim there were 13 million less music buyers in the US in 2008 compared to 2007. Consumer explanations for this include the recession, over-priced CDs, and that they were happy with their existing collections. However, NPD also reports that 19% of consumers are listening to music on social networks, while the proportion rises to nearly half of US teenagers.