It's a very interesting question. I did consult with the member of the NHL who sits on our technical committee and asked him if I could get some data. It had to be minimal data on numbers, types and where they were struck. His first response was, “I don't think they'll release that to you, but I'll try.” His second response was, “I was right the first time; they won't release it to you.” We're in the dark until such time as they make something known to the general public.
Evidence of meeting #10 for Subcommittee on Sports-Related Concussions in Canada in the 42nd Parliament, 1st session. (The original version is on Parliament’s site, as are the minutes.) The winning word was work.
A video is available from Parliament.