| Value | Category | Cases | |
|---|---|---|---|
| 1 | Once a month | 180 |
74.4%
|
| 2 | Once in 3 months | 26 |
10.7%
|
| 3 | Once in 6 months | 7 |
2.9%
|
| 4 | Only once | 29 |
12%
|
| Sysmiss | 271 |