| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 5 |
1.1%
|
| 1 | has certificate | 0 |
0%
|
| 2 | registered | 429 |
97.5%
|
| 6 | other | 3 |
0.7%
|
| 8 | don't know | 3 |
0.7%
|
| Sysmiss | 44174 |