| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1.Mandatory | 6 |
31.6%
|
| 2 | 2.Voluntary | 3 |
15.8%
|
| 6 | 6.Free | 10 |
52.6%
|
| 9 | 9.Missing | 0 |
0%
|
| Sysmiss | 412 |