| Value | Category |
|---|---|
| 1 | Pre-school |
| 2 | primary(I-IV) |
| 3 | gymnasium (V-IX) |
| 4 | lyceum, secondary general(X-XII) |
| 5 | secondary vocational |
| 6 | secondary professional, higher school |
| 7 | higher-1st cycle |
| 8 | higher-2nd cycle (PhD) |
| 9 | higher- other (medicine, archytecture,etc.) |
| Sysmiss |