Calculations of the population on 1 January of each year are consistent with United Nation's standard definition of population assessment, which is based on the concept of ordinary settlement.
Age definitions derive from:

• Law 18/2017 "For the Rights and Protection of the Child", Article 3/4: "Child" is every person under the age of 18;
• 10-19 years old and 10-24 years old are based on UNICEF's international terminology - 'Programmatic Guide for the Second Decade' (2018), and refers to adolescents and young people respectively;
• Law 75/2019 "For Young People", Article 3 defines young people as 15-29 years old.

 Source: INSTAT