| Value | Category | Cases | |
|---|---|---|---|
| 1 | more than once a year | 25 |
4.8%
|
| 2 | once a year | 163 |
31.4%
|
| 3 | every three years | 26 |
5%
|
| 4 | first time that was done | 272 |
52.4%
|
| 6 | other | 33 |
6.4%
|
| Sysmiss | 12396 |