| Value | Category | Cases | |
|---|---|---|---|
| 1 | Once | 1092 |
11.9%
|
| 2 | Twice | 685 |
7.4%
|
| 3 | Three times or more | 551 |
6%
|
| 98 | Don't know | 170 |
1.8%
|
| 99 | Not applicable | 6697 |
72.8%
|
| Sysmiss | 61441 |