| Value | Category | Cases | |
|---|---|---|---|
| 99 | Mising | 0 |
0%
|
| 1984 | 1 |
2.7%
|
|
| 1988 | 30 |
81.1%
|
|
| 1989 | 3 |
8.1%
|
|
| 1990 | 1 |
2.7%
|
|
| 1994 | 1 |
2.7%
|
|
| 2005 | 1 |
2.7%
|
|
| Sysmiss | 1688 |