I think the better graph to help explain this is on slide 9. It essentially tracks the major events that have occurred.
What we're seeing here in terms of refinery margins is the difference between the price of crude oil and how much a refiner can get to sell it to a retailer. What we're noticing now in terms of the recent hike is really a question of the supply crunch, or how much capacity is in the system to balance supply and demand.
As I mentioned before, the 30 different events that have occurred this year alone have constrained some of the capacity of these refiners. Some of them, actually pretty important ones, have occurred in Canada.