That depends on price, but currently there really is a lot of reserve out there, and as prices move up, the more uneconomical reserve that isn't counted today comes into the fold. So the number I gave you of 175 billion barrels is at today's price and today's technology.
If technology improves and prices change.... The total amount of oil sands in the ground is as big as 1.6 trillion barrels. Now, they believe that only 300 billion of that is recoverable, but if technology changes, it could push it out there.
So I don't see a point where you can say that on this date we will have the end of oil.