| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 2 |
50%
|
| 1 | Has certificate | 1 |
25%
|
| 2 | Registered | 0 |
0%
|
| 8 | DK | 1 |
25%
|
| Sysmiss | 9053 |