| Value | Category | Cases | |
|---|---|---|---|
| 1988 | 1 |
1.3%
|
|
| 1992 | 1 |
1.3%
|
|
| 1996 | 3 |
3.9%
|
|
| 1998 | 3 |
3.9%
|
|
| 2000 | 6 |
7.9%
|
|
| 2001 | 2 |
2.6%
|
|
| 2004 | 1 |
1.3%
|
|
| 2005 | 4 |
5.3%
|
|
| 2006 | 5 |
6.6%
|
|
| 2007 | 6 |
7.9%
|
|
| 2008 | 11 |
14.5%
|
|
| 2009 | 13 |
17.1%
|
|
| 2010 | 10 |
13.2%
|
|
| 2011 | 10 |
13.2%
|
|
| Sysmiss | 385 |