| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 1 |
0.2%
|
| -77 | 1 |
0.2%
|
|
| -9 | Don't know (spontaneous) | 8 |
1.9%
|
| -7 | Does not apply | 0 |
0%
|
| 1 | Yes | 38 |
9.1%
|
| 2 | No | 371 |
88.5%
|
| Sysmiss | 341 |