| Value | Category | Cases | |
|---|---|---|---|
| 1 | less than a month | 680 |
77.4%
|
| 2 | 1-2 months | 155 |
17.6%
|
| 3 | 2-3 months | 29 |
3.3%
|
| 4 | more than 3 months | 15 |
1.7%
|
| Sysmiss | 903 |