| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 8 |
24.2%
|
| 1 | Has certificate | 10 |
30.3%
|
| 2 | Registered | 13 |
39.4%
|
| 8 | Don't know | 2 |
6.1%
|
| 9 | 3 | ||
| Sysmiss | 36394 |