|Value||% Year-over-year variation|
|Aged less than 30||270,361||251,947||522,308||3.8||3.5||3.7|
|From 30 to 44 years||691,172||606,079||1,297,251||-1.0||-0.7||-0.9|
|From 45 to 54 years||479,142||409,085||888,227||4.0||3.8||3.9|
|Aged 55 and over||301,904||253,641||555,545||5.7||6.0||5.9|
|Source: Idescat. Contributors and affiliations to Social Security based on Contributors' Registered Place of Residence.|
|Note: The data refer to the number of contributors registered the last day of the month.|
The Affiliation to Social Security is compulsory for all people in the Social Security's field of application and unique for the lifetime of the worker. A person is considered to be affiliated at any given time when they are registered for one or more Social Security regimes.
Affiliations to the various Social Security regimes correspond to situations which give rise to the obligation to contribute, that is, from the perspective of affiliations, one person is counted as many times as their situations, either on the same or different regimes. However, from the point of view of the affiliates, they are only counted once, regardless of the number of affiliations.
Considering that the variable "residence affiliate" and the main demographic variables (sex, age and nationality) which comprise the archives of affiliations of the General Treasury of Social Security may not be up-to-date, Idescat treats these variables by addressing them with those of the Population Register of Catalonia, thus enriching the original file.
The information on contributors refers to the last day of each quarter.