Key Demographic Concepts and Population Statistics
I. Official Records and Key Demographic Concepts
Population Census
A statistical and official document that includes the individual results of the total population of one country at a given time.Municipal Register (Padrón Municipal)
An administrative record containing the official count of inhabitants of a municipality. Its formation, maintenance, revision, and custody correspond to the municipality, and it is constantly updated.Civil Registry
The official body that records births, deaths, and changes in the marital status of the population.Cadastre (Land Registry)
A census and statistical document detailing rustic (rural) and urban properties.Informal Economy (Underground Economy)
Economic activity conducted fraudulently, regardless of the law.II. Population Dynamics and Movement
Natural Movement of Population
The population increase or decrease in a given location due to natural causes (births and deaths).Baby Boom (Spain)
An expression used to refer to the significant increase in births that occurred in Spain from the late 1950s and early 1960s until 1974–1975.Migration, Emigration, and Immigration
Population movement in geographical space. If a population leaves its place of origin, it is emigration. If a population reaches a destination, it is immigration.Net Migration
A mobility index that values the difference between immigration and emigration. If a country has more immigration than emigration, the balance is positive; conversely, it is negative.Rural Exodus
Emigration from rural areas to industrial (urban) areas.Pendulum Movement (Commuting)
The daily movement (commuting) from the place of residence to the place of work.III. Demographic Rates and Formulas
A. Population Structure and Density
Population Density
The relationship between the total population and the total area.
Formula: Total Inhabitants / Total Area = hab/km²
Sex Ratio
The relationship (ratio) between the number of men and women in a population.
B. Fertility and Mortality Rates
Crude Birth Rate
Formula: (Births in a year × 1000) / Total Population = births per thousand inhabitants
Total Fertility Rate (TFR)
An indicator that measures the average number of children born per woman of childbearing age.
General Fertility Rate
Formula: (Births in a year / Women of childbearing age) × 1000
Crude Marriage Rate
The number of marriages per year per thousand inhabitants.
Infant Mortality Rate
The number of deaths of infants under one year of age.
Formula: (Deaths of infants <1 year × 1000) / Total Live Births = deaths per thousand
C. Population Growth and Indices
Absolute Natural Growth (Vegetative Growth)
Formula: Births - Deaths
Relative Natural Growth Rate
The difference between the Crude Birth Rate and the Crude Mortality Rate, usually expressed per thousand inhabitants.
Absolute Net Migration
Formula: Number of Immigrants - Number of Emigrants
Total Population Growth (Real Growth)
Formula: Absolute Natural Growth + Absolute Net Migration
Youth Index
The proportion of the young population (typically <16 years) relative to the total population.
Formula: (Population <16 years / Total Population) × 100 = Percentage
Aging Index
The proportion of the elderly population (typically >64 years) relative to the total population.
Formula: (Population >64 years / Total Population) × 100 = Percentage