The Municipal register is the administrative register where municipality inhabitants are recorded. The respective town councils are responsible for its formation, maintenance, revision and custody and its update is obtained from the revision of the municipal register referring to 1 January of each year, which is approved by the Government at the INE's request, after the favourable report by the Registration Board.
In 1996 a modification of register regulations was carried out. A new continuous and computerised management system for municipal registers was established, based on the coordination of all of them by the National Statistical Institute.
Based on the aforementioned regulations, the last register renewal was carried out, referred to 1 May, in 1996. This was the starting point for the new register system. The revision to 1 January 1998 was the first update to be carried out in agreement with the new system.
The statistical use of the register to 1 January each year is made from a file arising from the INE registry base from the which the proposal of official figures is obtained. The basic variables contained in the register which are likely to be used statistically are filtered. Crosses are made by: place of residence, sex, age, nationality and place of birth and broken down up to municipal level and by sex, nationality and age broken down up to census level.