What does the mechanical population growth rate mean?

The mechanical growth rate of population refers to the population change rate caused by the immigration and emigration of a country or region in a specific period. Population growth refers to the increase or decrease of a country's population in a certain period of time, usually due to the comprehensive effects of birth, death, immigration and emigration, and the growth rate is the growth rate. Therefore, the mechanical growth rate of population refers to the ratio of population changes caused by immigration and emigration in a certain period of time in a country or region. Population growth can be divided into two types: natural growth refers to the population increase caused by the birth rate higher than the death rate, and the natural growth rate is determined by both birth rate and death rate, and its growth rate depends on the natural growth rate of population; The mechanical growth of population refers to the population changes caused by population migration (immigration and emigration). When a region receives more immigrants, the mechanical growth of population is positive, which means the population increases. When an area loses more immigrants, the mechanical growth of population is negative, which means that the population decreases.