| Value | Category | 
|---|---|
| 1 | director and owner od enterprise (public and private sector) | 
| 2 | proefessionals and artists (with university diploma) | 
| 3 | qualified blue collars | 
| 4 | white collars | 
| 5 | service sector (trade, caterer, craftsman) | 
| 6 | unqualified and semi-qualified blue collars | 
| 999998 | refusal | 
| 999999 | dontknow | 
| Sysmiss |