| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1.Mandatory | 30 |
18.4%
|
| 2 | 2.Voluntary | 16 |
9.8%
|
| 6 | 6.Free | 117 |
71.8%
|
| 9 | 9.Missing | 0 |
0%
|
| Sysmiss | 268 |