| Value | Category | Cases | |
|---|---|---|---|
| 1986 | 1 |
0.3%
|
|
| 1991 | 1 |
0.3%
|
|
| 1993 | 56 |
18.8%
|
|
| 1994 | 6 |
2%
|
|
| 1995 | 7 |
2.3%
|
|
| 1996 | 144 |
48.3%
|
|
| 1997 | 83 |
27.9%
|
|
| Sysmiss | 12 |