| Value | Category | Cases | |
|---|---|---|---|
| 1986 | 2 |
20%
|
|
| 1987 | 2 |
20%
|
|
| 1989 | 1 |
10%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9999 | Missing | 5 |
50%
|
| Sysmiss | 4635 |