| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.1%
|
| 1 | Never or do not compare | 78 |
10.6%
|
| 2 | Once a year or less frequent | 256 |
34.6%
|
| 3 | Two or three times a year | 168 |
22.7%
|
| 4 | Monthly or more often | 236 |
31.9%
|
| Sysmiss | 357 |