INTRODUCTION
Demography is the study of human populations. It is an important part of sociology and the other social sciences because all persisting social aggregates- societies, states, communities, racial or ethnic groups, professions, formal organizations, kinship groups, and so on-are also populations. The size of the population, its growth or decline, the location and spatial movement of its people, and their changing characteristics are important features of an aggregate whether one sees it as a culture, an economy, a polity, or a society. As a result some anthropologists, economists, historians, political scientists, and sociologists are also demographers, and most demographers are members of one of the traditional social science disciplines [4] .the beginning of the 21st century demographic factors have become a crucial determinant of global security. They steadily and dynamically change the formal as well as contextual aspect of security issues. Some contemporary demographic trends have a specific character, and their diversity grows.
Demographic prognoses are the basis for the contemplation about future social developments.
In some areas population growth will exacerbate environmental degradation, competition for scarce resources, vulnerability to disease, support for extremist political and religious movements, and sometimes violent conflict. Chronic high fertility rates in developing nations with narrowly based elites and weak institutions are particularly vulnerable.from rural to urban areas, or legally or illegally across national boundaries, will evoke tensions, discrimination, and violence; strain health-care delivery systems; and contribute to disease outbreaks, particularly in receiving areas.risk is high that some allies in the developing world will be destabilized by migratory population flows.fertility rates between ethnic groups with mixed settlement patterns and historical enmity within countries and between neighboring countries will exacerbate instability and conflict, which could ultimately change the balances of power in some regions.in the structure of the world population are the subject of attention of many scientists as well as world organizations. Since the population changes have also economic and social effects, it is evident that in the period of rapid population changes there is a need and significant demand for information and data concerning the future development of population and its parameters.
1. DEMOGRAPHIC FORECASTS
research object of demography is population. Population can not be taken as a static element; rather it is characterized by a strong dynamics in quantity, structure, spatial distribution and other features. At the same time, changes of various features are, as a general rule, mutually interconnected in a chain way, and they account for a characteristic and vital process of each population. ' own dynamics involves a great amount of processes that at various geographical levels act in different ways and incorporate specific problems. Population growth requires a parallel growth of supplies and services to provide for basic human needs., Population growth exerts pressure on the employment market, GDP production and social stability [1] .qualified decision in the sphere of economy, social affairs, employment, education , health care and accommodation can not be made without qualified, properly structured, variable and prompt demographic information. The importance of demographic information further increases with the significant changes in reproductive behavior leading to a transformation of the population structure as well as family and household composition. Apart from information about the past and current population development, information about expected development is needed for decision processes.
In +2003 the UN published a prognosis of the world population, which in contrast to the previous long-term one for the period up to 2150, has a significantly longer time horizon - up to the year +2300. But it is necessary to say that the results for such a long-term prognosis have to be taken with a grain of salt. As more useful we can take results for the period up to the year 2050 [1] .prognosis is based on the finding that the population increase of the developing countries caused by high birth rate has slowed down, and it is proposed that it will be gradually slowing down in the next period. Thus it will be comparable to the situation in the highly developed countries, where, on the contrary, the prognosis supposes an increase in the contemporary low birth rate. Everywhere, an increase in the average life expectancy is expected.the UN projection the world population is supposed to be 8.92 billion people by 2050.world population will reach its maxi...
