| Value | Category | Cases | |
|---|---|---|---|
| 0 | 0. never | 3032 |
67.4%
|
| 1 | 1. once or twice in a year | 259 |
5.8%
|
| 2 | 2. once or twice in a term | 789 |
17.5%
|
| 3 | 3. once or twice in a month | 318 |
7.1%
|
| 4 | 4. every week | 100 |
2.2%
|
| 77 | 77. d/r | 0 |
0%
|
| 99 | 99. missing | 0 |
0%
|
| Sysmiss | 40 |