Mobile music revenues will be $429.3m this year, rising to $1.68bn by 2016, according to new predictions published by eMarketer.

The company claims that ‘ad-supported’ services will account for 68.7% of those 2012 revenues, with subscription-based services providing 17.2% and download stores 14.1%.

However, the subscription forecasts only include services that are “exclusive to mobile devices” and exclude those that are “accessed via multiple platforms”. So not Spotify, Deezer, Rdio, Rhapsody, MOG… In fact, very few of the higher-profile streaming music services in 2012.

At a time when two thirds of iTunes Store purchases happen on iOS devices rather than computers – this according to Apple’s Eddy Cue at the recent iPhone 5 launch – and when people’s decision to pay $9.99 a month for a streaming service is based mostly (but not entirely) on mobile access, the idea of nailing down ‘mobile’ music revenues is increasingly tough.