| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 92 |
12.4%
|
| 1 | has certificate | 121 |
16.3%
|
| 2 | registered | 526 |
70.7%
|
| 8 | don't know | 5 |
0.7%
|
| Sysmiss | 12205 |