| Value | Category | Cases | |
|---|---|---|---|
| 1 | monthly | 18 |
5.1%
|
| 2 | 3 months | 171 |
48.4%
|
| 3 | 6 months | 25 |
7.1%
|
| 4 | year | 139 |
39.4%
|
| Sysmiss | 16077 |