| Value | Category | Cases | |
|---|---|---|---|
| 1 | per month | 167 |
8.5%
|
| 2 | Once per 3 months | 170 |
8.7%
|
| 3 | Once every 6 months | 162 |
8.2%
|
| 4 | Once a year or less | 276 |
14.1%
|
| 5 | Not once | 1138 |
57.9%
|
| 6 | I do not know | 51 |
2.6%
|
| Sysmiss | 58 |