| Value | Category | Cases | |
|---|---|---|---|
| 1982 | 1 |
0.5%
|
|
| 1988 | 1 |
0.5%
|
|
| 1989 | 1 |
0.5%
|
|
| 1990 | 1 |
0.5%
|
|
| 1991 | 8 |
3.9%
|
|
| 1992 | 45 |
21.7%
|
|
| 1993 | 49 |
23.7%
|
|
| 1994 | 24 |
11.6%
|
|
| 7777 | 76 |
36.7%
|
|
| 9999 | 1 |
0.5%
|
|
| Sysmiss | 9422 |