As game sales continue to fall at traditional retail outlets, a number of digital distribution platforms are enjoying significant year-over-year revenue growth.

While NPD reported that US games industry sales suffered a fourth consecutive month of year-over-year declines in June, Valve saw a 97 per cent increase in download sales year-over-year during the month, and competitor Direct2Drive recorded a sales increase of 56 per cent.

Earlier this month Microsoft also announced that, in the first half, the number of paid downloads via Xbox Live jumped 73 percent year-over-year.

However, industry analyst Michael Pachter from Wedbush Morgan told IGN that online sales currently only make up around five per cent of monthly game sales.

"Downloads are probably $1-2 billion worldwide this year, compared to a $26 billion packaged goods market,” he said.