| Value | Category |
|---|---|
| 0 | None |
| 1 | Up to std 1 |
| 2 | Std.2 |
| 3 | Std.3 |
| 4 | Std.4 |
| 5 | Std.5 |
| 6 | Std.6 |
| 7 | Std.7 |
| 8 | Std.8 or equivalent |
| 9 | Std.9 or equivalent |
| 10 | Std.10 or equivalent |
| 11 | Std.10 plus one year |
| 12 | Std.10 plus two years |
| 13 | Std.10 plus three years |
| 14 | Std.10 plus four years |
| 15 | Std.10 plus five or more years |
| 16 | Unknown |