| Value | Category | Cases | |
|---|---|---|---|
| 1978 | 1 |
0.3%
|
|
| 1983 | 1 |
0.3%
|
|
| 1985 | 2 |
0.7%
|
|
| 1992 | 56 |
18.4%
|
|
| 1993 | 7 |
2.3%
|
|
| 1994 | 10 |
3.3%
|
|
| 1995 | 110 |
36.1%
|
|
| 1996 | 99 |
32.5%
|
|
| 1997 | 19 |
6.2%
|
|
| Sysmiss | 8 |