Final answer:
The population growth rate is the actual difference in population size between censuses, expressed as a percentage, accounting for births, deaths, and migration.
Step-by-step explanation:
The actual differences between the two census counts, expressed in percent relative to the size of the population noted in an earlier census, and known as the measure of how fast a population changes in size over time is the population growth rate. The population growth rate considers several factors affecting population size, such as births, deaths, and migrations. The essential formula representing this concept is r = (b + i) - (d + e), where r is the population growth rate, b is the birth rate, i is the rate of immigration, d is the death rate, and e is the rate of emigration. When the birth rate exceeds the death rate, the population grows, and conversely, a population decreases in size when the death rate surpasses the birth rate.