| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1. Only once | 69 |
37.7%
|
| 2 | 2. Every year | 23 |
12.6%
|
| 3 | 3. Once in 3 months | 1 |
0.5%
|
| 4 | 4. Every month | 85 |
46.4%
|
| 5 | 5. Others | 5 |
2.7%
|
| 9 | 9. Missing | 0 |
0%
|
| Sysmiss | 163 |