nrur: Natural-resource-usage Rate
Variable
Global
Natural-resource-usage Rate []
nrur = p * clip ( nrun , nrun1 , swt2 ,time)* nrmm

nrur in the updating graph: ( how to read )
In nodes
nrmm : natural-resource-from-material multiplier
nrun : natural-resource usage normal (natural resource units/person/year)
nrun1 : natural-resource usage normal no. 1 (natural resource units/person/year)
p : population
swt2 : switch time no. 2 for nrun (years)
Out nodes
nr : natural resource