I just have a couple of comments with respect to that.
Some of the cyclical aspect you're seeing in those charts is seasonal. You do have the summer driving season, when there is a higher demand for gasoline. Certainly the supply and demand balance changes as you go into the spring as refiners try to build inventories of gasoline. That has an impact on the refining margin. Subsequently, as you go into the fall season, you see a drop-off in the demand for gasoline, so that has an impact on capacity utilization.
Then you have the seasonality of other products. Let's not forget that gasoline is only one of the products that are produced from a barrel of oil. One barrel of oil doesn't equal one barrel of gasoline. There are a number of other products, gasoline being the highest-value product.
So there are seasonal fluctuations with respect to the overall demand of what component of the barrel of oil is required for gasoline.