The Curves pictured here are known as Hubbert curves. They track the availability and production of scarce resources.
I have done some research on the concept of peak oil. A man named Marion King Hubbard developed the theory of “peak oil” in the 1950’s. He used a series of mathematical equations to track and predict the availability and production of limited resources. One of the resources he studied was petroleum reserves. Given the known amount of reserves at that time, he predicted that the peak production of oil would be around 2005. Here is a website that goes into the background of the theory:
The curves representing American production of oil track closely to the Hubbert theory. The difference in the theory and the actual data is that production is lasting longer than predicted.