| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 1033 |
34.5%
|
| 1 | Has certificate | 636 |
21.3%
|
| 2 | Registered | 1239 |
41.4%
|
| 8 | Don't know | 84 |
2.8%
|
| 9 | 105 | ||
| Sysmiss | 33333 |