Fertility the number of births in a year per 1,000 mid-year population.
In recent decades there has been a decline in fertility in all countries, with the exception of former colonial and underdeveloped countries, where fertility rates are still high. Along with the decline in the birth rate in these years in all developed countries, there has been a sharp reduction in mortality of the population, especially children. This certainly affects the fertility rate (the relative decrease of this indicator). In the years of the great Patriotic war, the birth rate in the USSR fell, and after the war was established at the level significantly below pre-war. On the birth rate in the postwar years, known influenced by the consequences of war - a significant reduction in the number of persons of productive age; moreover, is set to visible aging of the population. The main causes of low fertility in the USSR are also ongoing resettlement of large masses of the population from villages to towns, where the birth rate is usually lower; the employment rate of women in social production.
In the USSR provided a positive natural increase of the population (considering the relatively stable level of mortality). Population growth is determined by the difference between fertility and mortality. In 1970, the natural increase of population in the USSR was 9.2 per 1,000 population (17.4 births minus 8.2 deaths per 1000 inhabitants).
To determine the level of birth rate are fertility rate, expressed in the number of births per year (live births) per 1,000 population. For more accurate measurement of the level of birth rate applies total fertility rate (or fertility rate, special fertility rate - the ratio between the number of births in the year to the number of women in the period fertility (15-49 years), calculated per 1000 women. Cm. also Demographics.