World Population Prospects 2019

Population Division
Glossary of Demographic Terms
Indicator Topic Definition

Age-specific fertility rates

Fertility

Number of births to women in a particular age group, divided by the number of women in that age group. The age groups used are: 15-19, 20-24, ..., 45-49. The data refer to five-year periods running from 1 July to 30 June of the initial and final years.

Annual Population by age groups

Population

Annually interpolated de facto population as of 1 July of the year indicated classified by sex (male, female, both sexes combined) and by five-year age groups (0-4, 5-9, 10-14, ..., 95-99, 100+). Data are presented in thousands.

Births

Fertility

Average annual number of births over a given period. Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Births by age group of mother

Fertility

Number of births over a given period classified by age group of mother (15-19, 20-24, 25-29, 30-34, ...45-49). Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Child dependency ratio

Population

The ratio of the population under age x1 (e.g., 0-24) to the number of persons of working age x1-x2 (e.g., 25-64). It is expressed as number of dependants per 100 persons of working age (e.g., 25-64).

Crude birth rate

Fertility

Number of births over a given period divided by the person-years lived by the population over that period. It is expressed as number of births per 1,000 population.

Crude death rate

Mortality

Number of deaths over a given period divided by the person-years lived by the population over that period. It is expressed as number of deaths per 1,000 population.

Deaths by sex

Mortality

Number of deaths over a given period. Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Deaths under age 1

Mortality

Number of deaths under age 1 over a given period. Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Deaths under age 5

Mortality

Number of deaths under age 5 over a given period. Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Feminity Ratio by broad age groups

Population

Number of Males per 100 Females by various functional combination of age groups (0-14, 0-17, primary and secondary school ages, 15-24, 15-49, ..., 18+, 50+, etc.). De facto population as of 1 July of the year indicated. Figures are expressed per 100 female population.

Infant mortality

Mortality

Probability of dying between birth and exact age 1. It is expressed as deaths per 1,000 births.

Life expectancy at birth by sex

Mortality

The average number of years of life expected by a hypothetical cohort of individuals who would be subject during all their lives to the mortality rates of a given period. It is expressed as years.

Mean age at childbearing

Fertility

The mean age at childbearing is the mean age of mothers at the birth of their children if women were subject throughout their lives to the age-specific fertility rates observed in a given year.

Median age

Population

Age that divides the population in two parts of equal size, that is, there are as many persons with ages above the median as there are with ages below the median.

Mortality under age 5

Mortality

Probability of dying between birth and exact age 5. It is expressed as deaths per 1,000 births.

Net migration

Migration

Net number of migrants, that is, the number of immigrants minus the number of emigrants. It is expressed as thousands.

Net migration rate

Migration

The number of immigrants minus the number of emigrants over a period, divided by the person-years lived by the population of the receiving country over that period. It is expressed as net number of migrants per 1,000 population.

Net reproduction rate

Fertility

The average number of daughters that female members of a birth cohort would bear during their reproductive life span if they were subject throughout their lives to the observed age-specific fertility and mortality rates of the given time period. It is expressed as the number of daughters per woman.

Old-age dependency ratio

Population

The ratio of the population aged x2 and over (e.g., 65+) to the number of persons of working age x1-x2 (e.g., 25-64). It is expressed as number of dependants per 100 persons of working age (e.g., 25-64).

Old-age potential support ratio

Population

The ratio of the number of persons of working age x1-x2 (e.g., 25-64) to the population aged x2 and over (e.g., 65+). It is expressed as number of persons of working age x1-x2 (e.g., 25-64 years) per person aged x2 years or over (e.g., 65+).

Percentage by broad age groups

Population

Percentage of Total Population by various functional combination of age groups (0-14, 0-17, primary and secondary school ages, 15-24, 15-49, ..., 18+, 50+, etc.). De facto population as of 1 July of the year indicated. Figures are expressed per 100 population.

Percentage rural

Population

Rural population as a percentage of the total population.

Percentage urban

Population

Urban population as a percentage of the total population.

Population

Population

De facto population in a country, area or region as of 1 July of the year indicated. Figures are presented in thousands.

Population density

Population

Persons per square Kilometer.

Population by broad age groups

Population

De facto population as of 1 July of the year indicated classified by sex (male, female, both sexes combined) and by various functional combination of age groups (0-14, 0-17, primary and secondary school ages, 15-24, 15-49, ..., 18+, 50+, etc.). Data are presented in thousands.

Population by five-year age group and sex

Population

De facto population as of 1 July of the year indicated classified by sex (male, female, both sexes combined) and by five-year age groups (0-4, 5-9, 10-14, ..., 95-99, 100+). Data are presented in thousands.

Population by sex   

Population

De facto population as of 1 July of the year indicated classified by sex (male, female, both sexes combined). Data are presented in thousands.

Population change

Population

Population increment over a period, that is, the difference between the population at the end of the period and that at the beginning of the period. Refers to five-year periods running from 1 July to 30 June of the initial and final years. Data are presented in thousands.

Population density

Population

Population per square Kilometer.

Population growth rate

Population

Average exponential rate of growth of the population over a given period.  It is calculated as ln(P2/P1)/n where P1 is the population in mid-year t1, P2 is the population in mid-year t2, and n is the length of the period between t1 and t2. It is expressed as a percentage.

Population sex ratio

Population

Number of males per 100 females in the population.

Rate of natural population increase

Population

Crude birth rate minus the crude death rate. Represents the portion of population growth (or decline) determined exclusively by births and deaths. It is expressed as number of births per 1,000 population.

Rural population

Population

De facto population living in areas classified as rural (that is, it is the difference between the total population of a country and its urban population). Data refer to 1 July of the year indicated and are presented in thousands.

Sex ratio at birth

Fertility

Number of male births per one female birth.

Sex Ratio by broad age groups

Population

Number of Females per 100 Males by various functional combination of age groups (0-14, 0-17, primary and secondary school ages, 15-24, 15-49, ..., 18+, 50+, etc.). De facto population as of 1 July of the year indicated. Figures are expressed per 100 male population.

Total dependency ratio

Population

The ratio of the sum of the population under age x1 (e.g., 0-24) and that aged x2 and over (e.g., 65+) to the number of persons of working age x1-x2 (e.g., 25-64). It is expressed as number of dependants per 100 persons of working age (e.g., 25-64).

Total fertility rate

Fertility

The average number of live births a hypothetical cohort of women would have at the end of their reproductive period if they were subject during their whole lives to the fertility rates of a given period and if they were not subject to mortality. It is expressed as live births per woman.

Urban population

Population

De facto population living in areas classified as urban according to the criteria used by each area or country. Data refer to 1 July of the year indicated and are presented in thousands.

Women aged 15-49

Fertility

Number of women aged 15-49 as of 1 July of the year indicated, and that number as a percentage of the total female population as of 1 July of the year indicated. The number of women is presented in thousands.


Disclaimer: This web site contains data tables, figures, maps, analyses and technical notes from the current revision of the World Population Prospects. These documents do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.