| Value | Category | Cases | |
|---|---|---|---|
| 1 | At once | 59 |
31.9%
|
| 2 | Within a month | 23 |
12.4%
|
| 3 | Later than a month | 20 |
10.8%
|
| 4 | Don't know | 83 |
44.9%
|
| Sysmiss | 4359 |