| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1. Per day | 480 |
73.4%
|
| 2 | 2. Per month | 156 |
23.9%
|
| 3 | 3. Per semester | 2 |
0.3%
|
| 4 | 4 Per academic year | 2 |
0.3%
|
| 5 | 5.Per one school period | 2 |
0.3%
|
| 9 | 12 |
1.8%
|
|
| Sysmiss | 5927 |