System Model
The money in circulation is determined by the money created, destroyed (people and treasury), money saved, and the money spent. The graph in the system model is showing how the money in circulation is depended on the money spent. This has multiple factors, but the graph is focused on the money spent. It is downloadable. The Vensim app is free and is easy to access. You can download this and open it through the computer's downloads.
Link to System Model