| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 4 |
40%
|
| 1 | Has certificate | 1 |
10%
|
| 2 | Registered | 4 |
40%
|
| 8 | DK | 1 |
10%
|
| Sysmiss | 9047 |