Why haven't they figured out who the huge "unknown" is yet? It's been that way for quite some time..
I'm thinking ghash offloaded a chunk of their hashing to a new ip to keep it looking like they don't have much.
as has been said many times before. Unknown is not one entity, it is all unknown entities grouped together. if you are looking at blockchaininfo, they show a larger unknown that other sites do. Also ananimity is a feature of bitcoin, so people who wish to be unknown should be allowed to.