| Value | Category | Cases | |
|---|---|---|---|
| 777 | Don't Know | 0 |
0%
|
| 1991 | 2 |
25%
|
|
| 1992 | 1 |
12.5%
|
|
| 1993 | 3 |
37.5%
|
|
| 1994 | 2 |
25%
|
|
| Sysmiss | 5573 |