| Value | Category | Cases | |
|---|---|---|---|
| 0 | Neither certificate or registered | 1182 |
27.4%
|
| 1 | Has certificate | 1173 |
27.2%
|
| 2 | Registered | 1872 |
43.4%
|
| 8 | Don't know | 83 |
1.9%
|
| 9 | 131 | ||
| Sysmiss | 31989 |