| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 9 |
3.6%
|
| 1 | has certificate | 0 |
0%
|
| 2 | registered | 236 |
93.3%
|
| 6 | other | 1 |
0.4%
|
| 8 | don't know | 7 |
2.8%
|
| Sysmiss | 44361 |