| Value | Category | Cases | |
|---|---|---|---|
| 0 | 0. never | 2878 |
64.8%
|
| 1 | 1. once or twice in a year | 536 |
12.1%
|
| 2 | 2. once or twice in a term | 670 |
15.1%
|
| 3 | 3. once or twice in a month | 294 |
6.6%
|
| 4 | 4. every week | 60 |
1.4%
|
| Sysmiss | 100 |