| Value | Category | Cases | |
|---|---|---|---|
| 1 | Within past month | 6020 |
90.4%
|
| 2 | Within past 3 months | 266 |
4%
|
| 3 | Within 6 months | 108 |
1.6%
|
| 4 | More than 6 months ago | 262 |
3.9%
|
| Sysmiss | 5824 |