U.K. download retailer 7digital has credited a 188% year-on-year growth in sales during 2007 to the removal of digital rights management (DRM) from tracks and the availability of high-quality MP3s.

The London-based company also benefited from an exclusive deal to supply bundled downloads of Radiohead's catalog. As a result, the band's "OK Computer" and "The Bends" albums made 7digital's top 10 sellers of the year, while Radiohead had a total of six albums in the top 20.

The company declined to reveal unit figures, but said Kylie Minogue's "X" was its No. 1 download album of 2007. Its top-selling MP3 track of 2007 was Dave Gahan's "Kingdom," followed by Minogue's "2 Hearts" and Pet Shop Boys' "Integral" (Dave Spoon mix). The re-release of Sex Pistols' "God Save the Queen" was their fourth biggest seller of the year, while Phil Collins made the top 20 with the re-release of "In the Air Tonight," thanks to the song's inclusion on a popular TV advert.

"The 2007 charts reveal the increasingly popularity of digital music," said Ben Drury, managing director of 7digital, in a statement.

Drury says consumers have responded positively to the arrival of DRM-free downloads.

"2008 is set to be the year DRM is gone for good," he added. "We've already seen all four majors make efforts to offer DRM-free downloads and by the summer DRM will likely be resigned to the history books.

"As the physical market continues to shrink, downloading will continue to grow in popularity. The consumer wants a universally compatible format free of DRM and we're finally able to offer this with MP3 320kbps downloads."

According to 7digital, over 70% of its catalog is available in MP3 format, while it claims all its downloads will be compatible with all digital music players by mid-2008.