| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 13 |
40.6%
|
| 1 | Has certificate | 10 |
31.3%
|
| 2 | Registered | 8 |
25%
|
| 8 | DK | 1 |
3.1%
|
| Sysmiss | 9025 |