| Value | Category | Cases | |
|---|---|---|---|
| 1 | Annual | 318 |
32.1%
|
| 2 | Every 2 years | 119 |
12%
|
| 3 | Every 3 years | 442 |
44.6%
|
| 9 | Other (specify)____ | 112 |
11.3%
|
| Sysmiss | 976 |