Hey Lordjames,
This analysis which I produce is a pretty good place to start.
https://busy.org/@miniature-tiger/market-share-of-the-steem-blockchain-by-application-june-2018-analysis
It uses the application information from the json metadata of each post.
I'll have a new version out for July in the next couple of days, making sure to include musing.io (and other platforms with non-standard json) this time!