| Value | Category | Cases | |
|---|---|---|---|
| 0 | Within the last three months | 2 |
1.6%
|
| 1 | Within the last 6 months | 3 |
2.5%
|
| 2 | During the last 12 months | 3 |
2.5%
|
| 3 | More than 1 year ago,but less than 2 years ago | 15 |
12.3%
|
| 4 | More than 2 years ago | 99 |
81.1%
|
| Sysmiss | 127 |