| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONLY ONCE | 1972 |
61.8%
|
| 2 | MORE THAN ONCE | 325 |
10.2%
|
| 9 | NO RESPONSE | 3 |
0.1%
|
| Sysmiss | 892 |
27.9%
|