| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 6 |
35.3%
|
| 1 | Has certificate | 4 |
23.5%
|
| 2 | Registered | 6 |
35.3%
|
| 8 | Don't know | 1 |
5.9%
|
| 9 | 2 | ||
| Sysmiss | 36411 |