| Value | Category |
|---|---|
| 0 | none |
| 1 | not completed P.1 |
| 2 | |
| 3 | |
| 4 | |
| 5 | |
| 6 | |
| 11 | P.1 |
| 12 | P.2 |
| 13 | P.3 |
| 14 | P.4 |
| 15 | P.5 |
| 16 | P.6 |
| 17 | P.7 |
| 18 | |
| 21 | J.1 |
| 22 | J.2 |
| 23 | J.3 |
| 31 | S.1 |
| 32 | S.2 |
| 33 | S.3 |
| 34 | S.4 |
| 35 | S.5 |
| 36 | S.6 |
| 37 | |
| 41 | post primary cert. |
| 51 | post sec. diploma |
| 61 | degree and above |
| 99 | don't know |
| Sysmiss |