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Notification to users of population estimates data


The State Statistical Office revised the series of population estimates for the period between the Census 2002 and the Census 2021. This activity of revising the population data series is a common practice worldwide after every census.

When using population estimates, it is extremely important to keep the following information in mind in order to use the most relevant data available from our website.

Methodological information

  1. The data set in the folder Population estimates based on the Census 2002 (archived data), for the period 31 December 2002 to 31 December 2020, was calculated based on data from the Census 2002, taking into account the number of births, deaths, immigrants and emigrants, according to the municipality where the persons lived and the year when the event occurred. All these data were obtained from administrative sources.
  2. In contrast to administrative data, censuses are conducted in the field, and therefore, certain differences are expected in the number of the population and its distribution across municipalities between two censuses.
  3. The difference in the number of the population between the estimates based on the Census 2002 and the results from the Census 2021 is due to unregistered emigration.
  4. Therefore, the SSO made a population estimate with the Census 2021 as a starting point, revising the calculations back to the Census 2002.
  5. The revision of the estimates is intended to provide more relevant population size data based on the more recent historical demographic situation, that is, calculations based on data from the Census 2021 versus data from the Census 2002.
  6. Based on the available data, the SSO managed to identify the emigrated persons who are not registered in the administrative sources, in contrast to those persons who were not enumerated in the Census 2021, and who are included in the total population.
  7. Unfortunately, the SSO was unable to find relevant sources of data for the year when the persons emigrated.
  8. Due to this shortcoming, the methodology used to estimate the population is based on a modified linear interpolation in which the modification refers to the intensity of migrations by calendar years, obtained from the statistics of other countries (known as mirror statistics).
  9. As a consequence of these factors, the SSO calculated the number of the population in the period between the two Censuses only at the country level.
  10. In addition, the SSO calculated the total population by statistical regions for the period 2017-2021.


Guidance for data users on the use of the revised population data series

  1. The valid official population data are the data calculated on the basis of the Census 2021, available in the folder Population estimates based on the Census 2021.
  2. The lowest territorial level for which these data are available is a statistical region, but only for the period from 1 January 2017 to 1 January 2021.
  3. Population estimates data based on the Census 2002 are archived historical data.

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