I'm not sure how you would even do a study to come up with an exact number, because you're looking at what people haven't bought. It's pretty hard.
It is fair to say that this is what my 13-year-old daughter would call a “no-brainer”, that if people think they're buying something from Canada and are actually buying something from somewhere else, a Canadian farmer has lost out. Consumers have gone out there to deliberately purchase that product because it has the word “Canada” on it. That tells them a lot of things—or they think it tells them a lot of things, which is the whole point of this. They think it means good quality, that it's local farmers, meaning Canadian farmers, and that by purchasing that product they're getting a bonus to themselves.
As to how to figure out a dollar figure, I don't know; you'd have to be a lot smarter than I am. But it is clear that if somebody is buying something they think is this product, when it's actually produced by somebody else, Canadians are losing market share, and they have continued to do that over the last number of years.