| Value | Category | Cases | |
|---|---|---|---|
| 1 | Within 3 months | 798 |
16.2%
|
| 2 | 3 months to 1 year | 1330 |
27%
|
| 3 | 1-3 years before | 1738 |
35.3%
|
| 4 | 4+ years before | 1062 |
21.6%
|
| Sysmiss | 20407 |