| Value | Category |
|---|---|
| -2 | na |
| -1 | missing |
| 1 | some primary |
| 2 | primary school graduates |
| 3 | some junior high |
| 4 | junior high school graduates |
| 5 | some high school |
| 6 | some vocational school |
| 7 | high school graduates |
| 8 | vocational school graduates |
| 9 | some university |
| 10 | university graduates |
| 11 | above university |
| Sysmiss |