| Value | Category | Cases | |
|---|---|---|---|
| 1987 | 39840 |
6.3%
|
|
| 1988 | 39840 |
6.3%
|
|
| 1989 | 39840 |
6.3%
|
|
| 1990 | 39840 |
6.3%
|
|
| 1991 | 39840 |
6.3%
|
|
| 1992 | 73920 |
11.7%
|
|
| 1993 | 73920 |
11.7%
|
|
| 1994 | 73920 |
11.7%
|
|
| 1995 | 73920 |
11.7%
|
|
| 1996 | 73920 |
11.7%
|
|
| 1997 | 64755 |
10.2%
|
|
| 1998 | 614 |
0.1%
|