| Value | Category | Cases | |
|---|---|---|---|
| 1 | mandatory | 20 |
2.1%
|
| 2 | voluntary | 74 |
7.7%
|
| 3 | both | 0 |
0%
|
| 4 | none | 873 |
90.3%
|
| Sysmiss | 5518 |