| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 946 |
24.5%
|
| 1 | Has certificate | 1129 |
29.3%
|
| 2 | Registered | 1727 |
44.8%
|
| 8 | Don't know | 54 |
1.4%
|
| 9 | 111 | ||
| Sysmiss | 32463 |