| Value | Category | Cases | |
|---|---|---|---|
| 1 | once a year | 5240 |
90.3%
|
| 2 | twice a year | 406 |
7%
|
| 3 | three times a year | 44 |
0.8%
|
| 4 | more than three | 116 |
2%
|
| Sysmiss | 54 |