| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 612 |
34.8%
|
| 1 | has certificate | 923 |
52.5%
|
| 2 | registered | 181 |
10.3%
|
| 8 | don't know | 18 |
1%
|
| 9 | 25 |
1.4%
|
|
| 11 | .Z | 13908 |