According to the latest data released by The NPD Group, iTunes now represents a quarter—25%—of all retail music sales in the United States, more than ten percent more than its closest competitor. Based on all music sold in the first half of 2009, iTunes sold 25 percent of it, up from 21 percent in 2008 and 14 percent in 2007. Walmart, which sells music through its brick-and-mortar stores, Walmart.com, and its Walmart Music Downloads initiative, accounted for 14 percent of music volume, followed by Best Buy in third. In digital music, iTunes’ lead is even larger, accounting for 69 percent of the market, followed by Amazon MP3 with 8 percent. Overall, digital music sales continue to make up a greater share of U.S. music sales, comprising 35 percent of all music sales, compared to just 20 percent in 2007 and 30 percent in 2008.