| Value | Category | Cases | |
|---|---|---|---|
| 1 | Within past month | 40 |
48.8%
|
| 2 | Within past 3 months | 15 |
18.3%
|
| 3 | Within 6 months | 3 |
3.7%
|
| 4 | More than 6 months ago | 24 |
29.3%
|
| Sysmiss | 12398 |