| Value | Category | Cases | |
|---|---|---|---|
| 1989 | 4 |
1.4%
|
|
| 1992 | 3 |
1%
|
|
| 1993 | 1 |
0.3%
|
|
| 1995 | 6 |
2%
|
|
| 1996 | 22 |
7.5%
|
|
| 1997 | 4 |
1.4%
|
|
| 1998 | 13 |
4.4%
|
|
| 1999 | 6 |
2%
|
|
| 2000 | 14 |
4.8%
|
|
| 2001 | 9 |
3.1%
|
|
| 2002 | 14 |
4.8%
|
|
| 2003 | 19 |
6.5%
|
|
| 2004 | 24 |
8.2%
|
|
| 2005 | 36 |
12.2%
|
|
| 2006 | 44 |
15%
|
|
| 2007 | 42 |
14.3%
|
|
| 2008 | 24 |
8.2%
|
|
| 2009 | 2 |
0.7%
|
|
| n/a | 7 |
2.4%
|