| Value | Category | Cases | |
|---|---|---|---|
| 1 | Weekly | 7 |
0.2%
|
| 2 | Monthly | 16 |
0.4%
|
| 3 | Once a year | 14 |
0.3%
|
| 9 | Other (specify) | 2 |
0%
|
| Sysmiss | 4056 |
99%
|