The AIGA surveys are a useful barometer but, as has been pointed out, they tend to be inaccurate. Specifically, they tend to run higher than normal. I put this disparity down to the (IMHO) probability that the very people who belong to AIGA in the first place tend to be on the higher-paid end of the scale to begin with.
There are variables you can calculate. First, what is the exchange difference between the US and Canadian dollars? You certainly should expect your salaries to be adjusted to account for this no matter what else you negotiate.
After that, you could figure what the cost of living difference would be moving from Calgary to, say, Montreal. That should be a reasonable equivalent to Chicago, I think.
Remember, too, to keep in mid things like health coverage. No national health down here. Either you or your employer (or both) are going to have to pay for that. And it isn't anywhere near cheap.