| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know | 0 |
0%
|
| -8 | Refused | 0 |
0%
|
| -5 | Not applicable | 0 |
0%
|
| -3 | Missing | 0 |
0%
|
| 1 | Months | 901 |
29.5%
|
| 2 | Years | 2157 |
70.5%
|
| Sysmiss | 23746 |