Natural Growth Rate

In demography and population geography, the natural growth rate (NGR) is the difference between birth rates (BR) and death rates (DR), that is, NGR = BR–DR. Along with net migration, natural growth rates are one of the two fundamental components of demographic change. For the world as a whole, natural growth rates are the only measure of population change, although for any unit less than that both natural growth and net migration must be taken into account.

Historically, natural growth rates have been very low, often zero, and at times, when mortality exceeded fertility (such as during famines or plagues), even negative. Only with the Industrial Revolution and the concomitant reductions in death rates (not a rise in birth rates) did natural growth rates rise, leading ...