| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 399 |
37.4%
|
| 1 | Has certificate | 276 |
25.8%
|
| 2 | Registered | 372 |
34.8%
|
| 8 | DK | 21 |
2%
|
| 9 | 20 | ||
| Sysmiss | 7969 |