| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1.Mandatory | 177 |
41.6%
|
| 2 | 2.Voluntary | 24 |
5.6%
|
| 6 | 6.Free | 217 |
51.1%
|
| 9 | 9.Missing | 7 |
1.6%
|
| Sysmiss | 6 |