How much storage does your typical private Docker registry deployment use?

I have been googling around trying to find information from companies talking about how much they are using Docker, specifically regarding if they are using their own private registry deployments (either their own servers or via one of the cloud services) and how much storage space that is using. I was unable to find any numbers talking about it. I couldn’t even find how much space Docker Hub is using for its registry to store all the images they do.

Could anyone point me towards information like that? Or if you’re working somewhere that does deploy a private registry, can you give me some info from your own experience?