The growth of the population is the sum of two indicators - natural and migration increase. Is the difference between the current level of the demographic situation and the level of the earlier period. The length of time over which the calculation is performed is called settlement and can be short-term (from one month to several years) and long-term (5, 10, 15, 25, 100 years).
Natural increase - the positive difference between the number of births and deaths (the number of births is greater than the number of deaths). For example, in Russia, according to the August 2009 born of 151.7 thousand people died 150,7 thousand people, so a natural increase of the population amounted to a thousand people. It is believed that if the birth rate exceeds the death rate, the reproduction of the population expanded. If these numbers are approximately equal, simple reproduction. If the death rate exceeds the birth rate, reproduction is narrowed, there is a strong demographic decline.
Migration (or mechanical) increase of the positive difference between the number of arrivals in a country of people from other countries and the number of departures from it citizens.
To determine the General pattern of demographic change in country coefficients of growth of the population. The rate of natural increase is the difference between the number of births and deaths over a period divided by the total number of the population. The migration growth of the population is the difference between the number of arrivals to the country citizens and the number of emigrants divided by total population. Accordingly, the overall rate of growth of the population is the sum of these coefficients.
Population growth is generally measured in percentage, so the resulting ratio is multiplied by 100. The total population is taken at the beginning of the billing period.
Based on the data and analysis population growth rate can predict the development of the situation in the coming periods.
Advice 2 : How to determine the rate of natural increase
Economic and social planning of any country is based on the projected change in the population. Citizens are at the same time its labor and consumer resource for the evaluation of which is necessary to determine the rate of natural increase.
The name of the natural population growth speaks for itself. The increase or decrease in the population caused by natural processes: birth and death. The magnitude and sign of this quantity depends on in what proportion are these two demographic factors.
If the number of births over the period of time exceeds the number of deaths, extended reproduction, in the case of approximate equality is simple. Well, the position at which the mortality rate is higher than the birth rate, is characterized by the mate reproduction.
Depending on the demographic situation in the country is critical can be expanded reproduction, and soienoe. Based on these calculations and predictions the leadership of the state takes steps to increase or decrease natural increase. For example, in China it is forbidden to have more than one child (except in the case of multiple births), the violation is punishable by fines, demotion and reduction in social status.
To determine the natural population growth can be an absolute or relative value. In the first case, to calculate the sufficient to calculate the difference between the numbers of citizens at the period end and the beginning. For example, suppose in some country N in 2010 were born 150 million people died and 143 million So the natural increase amounted to 7 million people.
The relative rate of natural population growth is a percentage that is equal to the ratio between the absolute value and the number of citizens at the beginning of the period. So, the natural increase in the state N in 2010 in relative terms amounted to (150 - 143)/143*100% ≈ 4,9 %.
The period for computing can be anything, both short-term and long-term, up to 100 years. In order to get data for calculations were as correct, carried out continuous monitoring of births and deaths. Receives the data from the original sources, namely hospitals and maternity homes. Each event, birth or death, confirmed by the evidence.
In addition there are also natural migration increase of the population. Its calculation is to compare the number of people arriving or departing from the country on permanent residence.