I'm a Windows Phone developer and I need to have information on marketshare of different versions of Windows Phone. I'm not interested in other OS, I just need to know marketshare of individual versions of Windows Phone so I can decide whether to develop and support app for particular version or not. I'm particulary interested in Windows Phone 7.X (it's awkward to devlop apps for both WP 7.X and WP 8.X)
I searched the web but I couldn't find any good source.