| Value | Category | Cases | |
|---|---|---|---|
| 1 | Less than a month | 1 |
1.1%
|
| 2 | 1-5 months | 23 |
26.4%
|
| 3 | 6-12 months | 25 |
28.7%
|
| 4 | over 1 year | 36 |
41.4%
|
| 9 | 2 |
2.3%
|
|
| Sysmiss | 340 |