| Value | Category | Cases | |
|---|---|---|---|
| 1 | At once | 1 |
25%
|
| 2 | Within a month | 0 |
0%
|
| 3 | Later than a month | 0 |
0%
|
| 4 | Don't know | 3 |
75%
|
| Sysmiss | 4540 |