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.
Rule of 72 An early reference to the rule is in the Summa de arithmetica (Venice, 1494. Fol. 181, n. 44) of Luca Pacioli (1445â€“1514). He presents the rule in a discussion regarding the estimation of the doubling time of an investment, but does not derive or explain the rule, and it is thus assumed that the rule predates Pacioli by some time.