Natural increase rate formula
In demography, the rate of natural increase (RNI) is a statistic calculated by subtracting the crude death rate from the crude birth rate of a given region.. This rate gives demographers an idea of how a certain country's population is growing. RNI excludes in-migration and out-migration, giving an indication of population growth based only on births and deaths. Because the term is always defined in terms of a given rate of birth minus a given rate of death, "natural increase" is itself a rate, i. e., the rate of net increase in births over deaths. It is also a ratio, where the birth rate in a specified period is the numerator and the death rate in the same period is the denominator. Definition: The rate of natural increase refers to the difference between the number of live births and the number of deaths occurring in a year, divided by the mid-year population of that year, multiplied by a factor (usually 1,000). It is equal to the difference between the crude birth rate and the crude death rate.