Well, it varies from day to day, to be honest.
Basically with the price gap, what we usually look at is, first of all, the difference between Brent, which is an international benchmark for light oil, and West Texas Intermediate or Canadian Par. It's been averaging $10 to $20 a barrel in the last couple of years. Normally those trade on par, so we're losing $10 to $20 a barrel in revenue for the companies, and of course that translates into fiscal impacts for light oil products. For heavier oil, we look at the differential between.... There are different heavy oil benchmarks. The one we look at is Western Canadian Select relative to West Texas Intermediate, and that differential has been as wide as $40 a barrel. It's normally more like $20.
We're losing $10 to $20 on light oil and another $10 to $20 more than usual on the heavy oil. The heavy oil is as much as $40 a barrel less—total—than what we would consider normal for heavy oil. That's where these figures come from, this $50 million a day that Brenda mentioned. We estimated that the total cost was $25 billion in 2012 if we got international benchmark prices for our oil, and of course that feeds through to fiscal impacts as well.