| Value | Category | Cases | |
|---|---|---|---|
| 1 | No | 1971 |
99.1%
|
| 2 | Once | 4 |
0.2%
|
| 3 | More than once | 0 |
0%
|
| 4 | Not applicable | 10 |
0.5%
|
| Sysmiss | 3 |