b: Births
Variable
Population sector
Births [Person/year]
b = clip (( tf * p2 *0.5/ rlt ), d , pet , time)

b in the updating graph: ( how to read )
In nodes
d : deaths
p2 : Population 15 To 44
pet : population equilibrium time
rlt : reproductive lifetime
tf : total fertility
Out nodes
cbr : birth rate
p1 : Population 0 To 14