• Data reference period
• Geographic localization (Portugal)
• Economic activity (CAE Rev. 2.1)
• Sex
• Occupation
• Work regime

• REFERENCE PERIOD:  Period to which the information refers and which may be a specific day or a time interval (month, fiscal year, calendar year, among others).
• ECONOMIC ACTIVITY:  Combination of resources such as labour, raw materials, equipment, etc., are joined, leading to the creation of specific goods or services. Regardless of the factors of production integrating the good or service produced, all activities generically imply an input of products (goods or services), a production process and an output of products (goods or services).
• OCCUPATION:  Trade or work modality, paid or unpaid, corresponding to a specific professional title, comprised of a set of tasks or activities with the same purpose and implying similar knowledge.
• SEX:  Biological and physiological characteristics that define men and women.

Sum of persons employed on the last business day of each month of activity in the year/ Number of months of activity during the year