| Value | Category |
|---|---|
| 1 | Primary or lower education |
| 2 | Incomplete secondary education |
| 3 | Secondary education (general or vocational school) |
| 4 | Special vocational education (technical college) |
| 5 | Incomplete higher education (at least 3 years of higher educational institution) |
| 6 | Higher education |
| 99 | Don't know |
| 999 | No answer |
| Sysmiss |