| Value | Category | Cases | |
|---|---|---|---|
| 0 | neither certificate or registered | 3 |
37.5%
|
| 1 | has certificate | 2 |
25%
|
| 2 | registered | 1 |
12.5%
|
| 8 | don't know | 1 |
12.5%
|
| 9 | 1 |
12.5%
|
|
| 11 | .Z | 15659 |