| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 701 |
33.3%
|
| 1 | Has certificate | 160 |
7.6%
|
| 2 | Registered | 1211 |
57.4%
|
| 8 | Don't know | 36 |
1.7%
|
| 9 | 79 | ||
| Sysmiss | 11884 |