ESS Standard for Quality Reports Structure (ESQRS)
National Statistical Institute
|Contact organisation unit|
Population and Housing Fund Statistics
|Contact person function|
Director "Demographic and Social Statistics" Directorate
|Contact mail address|
2, P. Volov Str.; 1038 Sofia, Bulgaria
|Contact email address|
|Contact phone number|
+359 2 9857 411
|Contact fax number|
The population and its structures are defined as of 31.12. of the respective year. The population number and structures at the end of each year are calculated based on the previous year data and data on natural and migration increase during the reference year.
In the census years, recalculations of the population are done as of the end of the respective and the previous year. The recalculations are based on the census results and the respective calculations for the natural and migration increase, received from the current demographic statistics for the reference year.
The concept "permanent population" is applied in calculation of the population and its structures. The persons are included, permanently living in the country (having current address) as of 31.12. of the respective year and who have not been absent from the country for more than 1 year period.
Demographic projections (the population perspective projections) are calculations done under settled in advance conditions for the future development of the fertility, mortality and migration. They give an idea for the population development during the projected period. Different scenarios for the population projections are used depending on the expected social-economic development of the country.
· Classification of Territorial Units for Statistical Purposes in Bulgaria (NUTS);
· Unified Classification of the Administrative-Territorial and Territorial Units in Bulgaria (UCATTU).
The data on population number and structures cover persons permanently living at the country territory no matter their citizenship and status. The population territorial distribution (by settlements, municipalities, districts and statistical regions) is done according to the country administrative-territorial division as of 31.12. of the reference year and current address officially stated address of residence.
The last demographic projection elaborated by the NSI concerns the development of population up to 2080 with a starting point - the country population as of 31.12.2016 and takes into account the number of demographic events in 2017. The projection is prepared by single ages for each year within the period. Data is published for five-year periods.
|Statistical concepts and definitions|
Population as of 31.12.
Persons permanently living (having current address) in the country as of 31.12. of the reference year and who have not been absent for more than 1 year period.
The population number and structures at the end of each year are calculated on the basis of the population data for the preceding year and the data for natural and mechanical movement of the population during the current year.
Average annual population
The average annual number of population is average arithmetical value of the population at the end of previous and the end of reference year.
The difference between the number of live births and the number of deaths during the reference year.
Natural increase rate
Calculated per 1 000 population and representing the difference between the number of live births and deaths during the year and the average annual population for the same year.
The difference between immigration into and emigration from the area during the year.
Net international migration is the difference between immigration into and emigration from the country.
The population age is calculated as of 31.12. in completed years based on date of birth, i.e. the age reached at the end of the reference year.
Population under, at and over working age
The age limits used for distribution of the population under, at and over working age defined according to the annually updated retirement age, adopted by the Council of Ministers.
Age dependency ratio
Ratio of the number of persons under 15 years of age and number of persons 65 and more per 100 persons aged 15 to 64 years calculated in percentage.
Old age dependency ratio
Ratio of the number of persons aged 65 and more per 100 persons aged 15-64 years calculated in percentage.
Rate of demographic ageing
Rate of increase of the population over working age (according to the respective age limits for male and female) compared to the previous year calculated in percentage.
Demographic replacement rate
Ratio between the number of population aged 15 to 19 years (persons entering working age) and the number of population aged 60 to 64 years (persons leaving working age) calculated in percentage.
Regional breakdown of the population is done according to the country administrative-territorial division as of 31.12. of the reference year - settlements, municipalities, districts and statistical regions.
· 1880 - 2011 by census years;
· 1946 - 2020 as of 31.12.;
· 2010 - 2020 on the NSI website.
For national projection - 2020 - 2080
For district projections - 2020 - 2080
Source of data on the population number and structures is the Information system "Demography" and the information on demographic events (births, deaths, marriages, divorces, migration) received from the Unified System for Civil registration and Administrative Service of Population.
|Frequency of data collection|
Exhaustively for all registered during the year demographic events.
Computer files are received from the Unified System for Civil registration and Administrative Service of Population (administrative source).
Data on demographic events is checked and controlled before to be loaded in the IS "Demography".
For successful processing, the initial notification should meet the system rules on validation and control.
The processed results are validated in respect the consistency of a single table and between the tables.
Data is processed by the IS "Demography" according to the rules for validation and control of the demographic events.
Data on population and demographic processes are presented annually to the Eurostat, UN and UNICEF - questionnaires filled in annually.
At national and regional level the main data users are ministries, agencies, national organisations and local authorities.
Data is presented to scientific institutes, universities, NGOs and others based on requests.
No user' satisfaction surveys are carried out.
Population data is available by sex, age (different groupings), residence (different territorial levels), citizenship and country of birth.
|Data completeness - rate|
|Accuracy and reliability|
|Sampling errors - indicators|
|Over-coverage - rate|
|Common units - proportion|
|Non response error|
|Unit non-response - rate|
|Item non-response - rate|
|Imputation - rate|
|Model assumption error|
|Data revision - policy|
Recalculations of the population at the end of reference year and for the previous one are done in the census years.
|Data revision - practice|
The recalculation of population is based on the census results and the respective calculations of the natural and migration growth for the reference year, received form the current demographic statistics.
|Data revision - average size|
|Timeliness and punctuality|
Data are published up to the end of April in the year following the reference year.
|Time lag - first results|
4 months after the reference date
|Time lag - final results|
4 months after the reference date
Data is released according to the terms.
|Punctuality - delivery and publication|
|Coherence and comparability|
|Comparability - geographical|
Data is collected and processed for the different territorial units using one and the same methodology and definitions.
|Asymmetry for mirror flows statistics - coefficient|
|Comparability - over time|
Changes of the methodology and definitions for different time periods are published in the survey methodology.
|Length of comparable time series|
|Coherence - cross domain|
|Coherence - sub annual and annual statistics|
|Coherence - National Accounts|
|Coherence - internal|
|Accessibility and clarity|
News release "Population and demographic processes"
· Population and demographic processes;
· Statistical Reference book;
· Statistical Yearbook;
· Booklet Bulgaria.
Data on population are available to all users of the NSI website under the heading Population (Demography, Migration and Projections): https://www.nsi.bg/en/node/6701
Information system Infostat: https://infostat.nsi.bg/infostat/pages/module.jsf?x_2=80 (Population) and https://infostat.nsi.bg/infostat/pages/module.jsf?x_2=122 (Population projections)
|Data tables - consultations|
Anonymised individual data can be provide for scientific and research purposes, and for individual request according to the Rules for the provision of anonymised individual data for scientific and research purposes.
Information service on request, according to the Rules for the dissemination of statistical products and services in NSI.
|Metadata - consultations|
|Documentation on methodology|
· Methodology on population and demographic processes: https://www.nsi.bg/sites/default/files/files/metadata/Pop_6_Metodology_population_en.pdf;
· Methodology on population projections.
|Metadata completeness – rate|
|Cost and burden|
|Confidentiality - policy|
· Law on Statistics;
· Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.
|Confidentiality – data treatment|
Individual data are not published in accordance with article 25 of the Law on Statistics. The publishing of individual data can be performed only in accordance with article 26 of the same law.