| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
13.3%
|
| 0 | None | 7 |
46.7%
|
| 1 | 2 |
13.3%
|
|
| 2 | 1 |
6.7%
|
|
| 5 | 1 |
6.7%
|
|
| 15 | 2 |
13.3%
|
|
| Sysmiss | 993 |