| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
20%
|
| 2 | 1 |
20%
|
|
| 8 | 1 |
20%
|
|
| 20 | 1 |
20%
|
|
| 22 | 1 |
20%
|
|
| Sysmiss | 346 |