| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know | 1 |
0.2%
|
| -8 | Refused | 0 |
0%
|
| -5 | Not applicable | 0 |
0%
|
| -3 | Missing | 12 |
2%
|
| 1 | Less than 6 months | 136 |
22.3%
|
| 2 | 6 months or more | 460 |
75.5%
|
| Sysmiss | 29501 |