iTunes usage almost doubled in 2006, a report claims.

A calculation of unique users of the service has been assembled by WebSiteOptimization using data from Nielsen//NetRatings. It shows iTunes usage grew 47.5 per cent in 2006, massively outpacing growth in use of Windows Media Player (2 per cent) or RealPlayer (9.1 per cent).

The report goes on to add that if iTunes usage continues to rise at this rate, it will pass the installed base of RealPlayer by the second quarter of this year. There are currently 27 million iTunes users, the report explains, and an additional 14 million QuickTime users.

"Apple should be whistling a happy tune this year. While iTunes continues to show stong double-digit growth rates, Windows Media Player growth appeared to slow over the past year," the report observes.

RealPlayer has 27 million users while Windows Media Player has 73 million.