| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 33 |
50.8%
|
| 2019 | 12 |
18.5%
|
|
| 2020 | 18 |
27.7%
|
|
| 2021 | 2 |
3.1%
|
|
| Sysmiss | 1381 |