| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
2.2%
|
| 0 | None | 115 |
85.8%
|
| 1 | 13 |
9.7%
|
|
| 2 | 2 |
1.5%
|
|
| 3 | 1 |
0.7%
|
|
| Sysmiss | 1 |