| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1. Per month | 65 |
61.3%
|
| 2 | 2. Per semester | 21 |
19.8%
|
| 3 | 3. Per year | 15 |
14.2%
|
| 5 | 5. Others | 5 |
4.7%
|
| 6 | 6. None | 0 |
0%
|
| 9 | 9. Missing | 0 |
0%
|
| Sysmiss | 233 |