| Value | Category | Cases | |
|---|---|---|---|
| 1980 | 2 |
3.3%
|
|
| 1992 | 2 |
3.3%
|
|
| 1997 | 1 |
1.6%
|
|
| 1998 | 5 |
8.2%
|
|
| 2000 | 1 |
1.6%
|
|
| 2001 | 2 |
3.3%
|
|
| 2002 | 4 |
6.6%
|
|
| 2003 | 3 |
4.9%
|
|
| 2004 | 1 |
1.6%
|
|
| 2005 | 2 |
3.3%
|
|
| 2006 | 6 |
9.8%
|
|
| 2007 | 18 |
29.5%
|
|
| 2008 | 13 |
21.3%
|
|
| 9999 | 1 |
1.6%
|
|
| Sysmiss | 385 |