The Republic of Azerbaijan includes Nakhchivan Autonomous Republic, 66 administrative regions, 77 towns, 257 settlements and 4260 rural settlements.
The current estimation of the population size is carried out based on results of last population census. The number of birth and arrivals are added to population size and number of death and departures is deducted from the size of population. The size of population is precise during period between censuses according to the results of the next population census.
Age is a number of completed years: for children under one year old - number of months and for infants under one month –number of days. The data on age are compiled by means of inquiry during the population censuses. This data are defined by means of current estimation according to movement of the population size from the age x to x + 1. The information on current registration of demographic events is taking into account during these estimations.
Different age groups are used depending on analysis purposes.
The data on population size by sex and age groups for 1926, 1939, 1959, 1962, and 1969 are given based on present population, while data for 1979-2009 is based on resident population.
Age intervals reflect exact years included in this intervals. For example, “20-24” covers the five year interval including from 20 to 25 years old.
Urban and rural population – based on place of residence the population is divided into urban and rural population. Urban places include towns and settlements, the rest settlements are considered as rural places.