A top-selling digital song of 2010 was “California Gurls” by Katy Perry (4.4 million).
U.S. music sales fell 2.4% in 2010 to 1.5 billion units, as CD sales plummeted nearly 20% while digital track sales were up just 1%, according to a report from Nielsen and Billboard. Digital track sales were 1.17 billion in 2010, up from 1.16 in 2009. While CD sales fell precipitously last year, digital album sales rose 13% to 863 million. The report notes that digital music accounted for 46% of all U.S. music purchases in 2010, up from 40% in 2009 and 32% in 2008, and digital track sales broke the 1 billion sales mark for the third straight year.