Guys he asks for a proportion, it is not like you are helping
I don't have a data. You'd need to find any surveys or analytics about the Hosting industry and different niches. Just check whether IDC, Gartner, Tier1Research or any other organization like these has published some data.
Gartner publishes an annual survey "Magic Quadrant for Web Hosting and
Hosted Cloud System Infrastructure
Services (On Demand)". go find one of their reports.