| Value | Category | Cases | |
|---|---|---|---|
| 1 | Once | 132 |
5.9%
|
| 2 | Twice | 148 |
6.7%
|
| 3 | Three times or more | 235 |
10.6%
|
| 98 | Don't know | 98 |
4.4%
|
| 99 | Not applicable | 1612 |
72.4%
|
| Sysmiss | 23217 |