The objectives of this statistical operation is to estimate:
- the national population by gender, age and marital status on eration 1st January
of each year;
- the regional and departmental population by gender and age group on 1st January of each year.
These population estimates are mainly used to calculate different demographic indicators: birth rate, mortality rate, total period fertility, death probability, life expectancy.
The population census is used as a base for annual population estimates. It sets the reference levels. Between two censuses, provisional estimates are carried out.
These become definitive once the results of a new census are known. After the 1999 total population census, total population estimates, by gender and age and marital status were therefore revised for the period from 1st January 1991 to 1st January 1999.
The population estimates published subsequently were based until 2008 on the results of the 1999 census, updated every year from civil status statistics (concerning births and deaths) and an estimate of net migration.
At the end of 2008, the definitive results of the new census became available, relating to 1st January 2006, and as a result, population estimates for 1st January 2000 and the following years were revised.
From now on, new definitive census results will be made available every year, changing the calendar of estimates.
New calendar of estimates:
In January of year n estimates "until the end of n-1" are published:
- national, regional and departmental population estimates relating to 1st January
of the year n-3 are revised and become definitive and are than combined with the latest
available results from the census;
- national population estimates for 1st January n-2 and 1st January n-1 are then revised, but remain provisional;
- regional population estimates for 1st January of year n-2 are revised and remain provisional;
- the first national population estimates for 1st January n are published, along with the first departmental population estimates for 1st January of year n-2 and the first regional estimates for 1st January of year n-1. At this point these estimates are provisional.