nr: Nonrenewable Resources
Variable
Nonrenewable resource sector
Nonrenewable Resources [Resource units]
nr = nr + dt*(- nrur )

nr in the updating graph: ( how to read )
In nodes
nri : initial nonrenewable resources
nrur : resource usage rate
nr : Nonrenewable Resources
Out nodes
nrfr : fraction of resources remaining
nr : Nonrenewable Resources