For employed persons and unemployed ones who ever worked (who answers items (1--5) of question 74, and if the answers (6--12) go to question 83
[Questions 79 through 82 asked of persons aged 7 or older who were employed or unemployed as indicated in questions 74 responses 1 through 5.]

77. Main economic activity current/previous (detailed employer type of work)

Main economic activity:
Is the main work of the establishment based on the (ISIC, rev4) and that contribute by the large proportion of the value added, whenever more than one activity exist in the establishment.