| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 2 |
40%
|
| 9 | 1 |
20%
|
|
| 15 | 1 |
20%
|
|
| 25 | 1 |
20%
|
|
| Sysmiss | 340 |