| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 21 |
36.8%
|
| 1 | Has certificate | 14 |
24.6%
|
| 2 | Registered | 21 |
36.8%
|
| 8 | Don't know | 1 |
1.8%
|
| 9 | 3 | ||
| Sysmiss | 36370 |