How is the population in a country or given area calculated?
The population of a given area is the number of people usually living in that area, and it is usually measured every 1st January.
The source is generally the most recent population census, which is an official survey to count the population, but population registers are increasingly used as well. Since a census is normally carried out every 10 years, each year the population figure is adjusted to update the data collected, taking into account the natural population change and the net migration.
The natural population change is calculated by comparing each year the number of births with deaths, whereas net migration compares the number of people who arrived to the country (immigrants) with the number of people who left (emigrants).
Example
For instance, in the EU on 1st January 2020, the population was estimated at 447.49 million people, while on 1st January 2019 it was estimated at 446.59 million. Therefore, during 2020 the population increased by 930 thousands people. Was this due to natural population change or net migration? As 4.1 million babies were born and 5.2 million persons died, there was a negative natural population change (-1.1 million). Therefore, the net migration was the reason for the increase.
What are some other important indicators about the population?
The fertility rate represents the average number of children that a woman could have over her childbearing age. It is calculated taking into consideration the currently average number of children born alive for different age groups.
The crude birth rate, instead, defines the number of births that occurred during the year compared to the population measured on that same year. It is then expressed as the number of new-born children every 1 thousand people.
Example
In 2020, 4 million children were born in the EU, which means that 9.1 births were registered every 1 000 persons (crude birth rate). This rate has decreased over the last 50 years: it was 10.4 in 2010, 10.6 in 2000 and 16.4 in 1970.
Among the EU Member States, France reported the highest fertility rate in 2020, as on average a woman would give birth to 1.83 children over her life, while the lowest fertility rate was recorded in Malta (1.13 live births per woman).
Inversely, the crude death rate is defined as the number of deaths occurred during a year compared to the population in that same year; the value is expressed as deaths occurring every 1 thousand persons.
The infant mortality rate records deaths of children aged less than one year compared to the number of live births, in a given year. The value expresses the number of infant deaths every 1 thousand live births.
Example
In 2020, some 5.2 million people died in the EU, registering almost 12 deaths for every 1 000 people (crude death rate). This rate was assessed around 10 over the last 40 years, but increased relevantly during the Covid-19 pandemic.
How long can a person expect to live? It is possible to have an idea thanks to the indicator of life expectancy.
The indicator of life expectancy at birth provides information on the number of years a new-born baby can expect to live. It takes into account the mortality conditions today and how likely it currently is to die at each age.
Life expectancy is normally calculated for the population as a whole, but it is also measured separately for women and men. In fact, results show that women can generally expect to live longer than men.
Example
Over the past 70 years, life expectancy at birth has increased of about 10 years for both men and women in the EU. Indeed, a baby born in 2020 is expected to live around 80 years, up to 83 years for a baby girl and 78 for a baby boy, whereas babies born in the 1960s were expected to live about 10 years less.
Population pyramid
A population pyramid helps to visualise the number of people by age group for a certain year. It usually places the oldest age group on top and the youngest at the bottom, usually showing figures referred to men on the left side and women’s on the right.
Population pyramids, EU, 2001 and 2015
(% of the total population)
Source: Eurostat (demo_pjangroup)
In the animation above, the population pyramids of 2001 and 2015 are compared. As you can see, in 2015, the age group with the highest share of the population was 45-49, while in 2001 it was 30-34 and 35-39. Only by looking at the shape of the pyramid, it is possible to see that the population is ageing, as the younger age groups’ bars are getting smaller and the older groups ones’ are becoming bigger.
Furthermore, the trend is confirmed by the change in the median age of the population: while in 2001 it was 38.3 years, it became 42.4 years in 2015.
