| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 31 |
2.1%
|
| 1 | has certificate | 0 |
0%
|
| 2 | registered | 1381 |
95%
|
| 6 | other | 17 |
1.2%
|
| 8 | don't know | 25 |
1.7%
|
| Sysmiss | 43160 |