The growth in digital music sales has been slowing in recent years, according to industry figures.
Sales grew 11-fold between 2004 and 2010 to an estimated $4.6bn (Â£2.9bn), the International Federation of the Phonographic Industry (IFPI) said.
But while revenues grew by 25% in 2008, that figure slipped to 12% in 2009 and to just 6% in 2010.
The group also warned of the challenges facing the industry from piracy, with 95% of music downloads made illegally.
"As an industry we remain very challenged," IFPI chief executive Frances Moore told the BBC.
"Some 95% of intellectual property is stolen.
"It doesn't just affect the record companies, it affects jobs. We have independent studies that show that something like 1.2 million jobs could be lost in the creative sectors by 2015 - something like 10% of the workforce."