I do this in part, so that you can have those numbers when reading the predictions being made for Saudi Aramco production, and how they are going to get it (thanks to Energy Bulletin for the pointer).

When you take this with the average amount of oil each well adds, then you can see how much, without that addition, the production from each country would have been.  Which should give some idea of the rates at which production would otherwise be declining.  That was the basic theory, but since you have to allow for when wells came on stream, and such factors, it did not prove the easy task I thought it might be.  But if you are looking for something to do . . . .