| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1. per day | 296 |
46.9%
|
| 2 | 2. per month | 162 |
25.7%
|
| 3 | 3. per semester | 59 |
9.4%
|
| 4 | 4. per academic year | 75 |
11.9%
|
| 5 | 5. per school period | 36 |
5.7%
|
| 9 | 9. Missing | 3 |
0.5%
|
| Sysmiss | 13600 |