| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 1 | 1 |
25%
|
|
| 2 | 1 |
25%
|
|
| 15 | 1 |
25%
|
|
| 31 | 1 |
25%
|
|
| Sysmiss | 357 |