| Value | Category |
|---|---|
| 1 | no schooling |
| 2 | unfinished elementary school |
| 3 | elementary school |
| 4 | vocational school -1-2 years |
| 5 | secondary, 3 years and school for skilled workers |
| 6 | second.4 years and school for highly skilled workers |
| 7 | gymnasium |
| 8 | post secondary |
| 9 | university |
| 10 | m.a. degree, specialization |
| 11 | doctorate |
| 98 | refusal |
| 99 | dontknow |