I would say that the primary importance is not financial, as seems to have been stressed in earlier sessions, and even in this session. That question, certainly in my world, is of relatively little consequence.
What I see all the time are students, and also librarians, to a certain extent, and faculty members suffering from copyright chill when they are in fact already doing research, private study, criticism, and review. They're scared to death of the copyright police, who might be out there. They over-interpret.
I can tell you that currently, at York University, I've been working for a year now on getting rid of all sorts of semi-official language in guidelines for students about academic integrity that conflate, say, plagiarism, on the one hand, with copyright infringement on the other hand, when the two really need to have a bright line between them. Merely putting that word in as an illustrative example of what fair dealing is I think would clarify it for those people enormously.
I can't give you any figures on this, because the phenomenon necessarily involves self-censorship up to this point. People are not going to tell you that, yes, they've been making these copies that may be dubious or are in a grey area. But self-censorship is certainly against the article 2 freedom of expression encouragement we would hope would be manifested in copyright legislation.