when calculating the rate of natural increase one does not include
Rate of natural increase In demographics, the rate of natural increase (RNI) is the crude birth rate minus the crude death rate.[1] This rate excludes population increase from in migration and out migration. When looking at countries, it gives an idea of what position in the Demographic Transition Model, but to find out how much a country is growing, the population growth rate should be observed. The Demographic Transition Theory explains the rate of natural increase relate to the economic growth.
Supply and demand When technological progress occurs, the supply curve shifts. For example, assume that someone invents a better way of growing wheat so that the cost of growing a given quantity of wheat decreases.  Otherwise stated, producers will be willing to supply more wheat at every price and this shifts the supply curve S1 outward, to S2â€”an increase in supply. This increase in supply causes the equilibrium price to decrease from P1 to P2. The equilibrium quantity increases from Q1 to Q2 as consumers move along the demand curve to the new lower price. As a result of a supply curve shift, the price and the quantity move in opposite directions. If the quantity supplied decreases, the opposite happens. If the supply curve starts at S2, and shifts leftward to S1, the equilibrium price will increase and the equilibrium quantity will decrease as consumers move along the demand curve to the new higher price and associated lower quantity demanded. The quantity demanded at each price is the same as before the supply shift, reflecting the fact that the demand curve has not shifted. But due to the change (shift) in supply, the equilibrium quantity and price have changed.