| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know | 3 |
0.1%
|
| -8 | Refused | 11 |
0.3%
|
| -5 | Not applicable | 0 |
0%
|
| -3 | Missing | 2 |
0.1%
|
| 1 | Less than 6 months | 1137 |
30.6%
|
| 2 | 6 months or more | 2564 |
69%
|
| Sysmiss | 26393 |