| Value | Category | Cases | |
|---|---|---|---|
| 1979 | 1 |
0.5%
|
|
| 1980 | 1 |
0.5%
|
|
| 1984 | 1 |
0.5%
|
|
| 1987 | 2 |
1%
|
|
| 1990 | 3 |
1.5%
|
|
| 1991 | 2 |
1%
|
|
| 1992 | 1 |
0.5%
|
|
| 1993 | 1 |
0.5%
|
|
| 1995 | 4 |
2.1%
|
|
| 1996 | 5 |
2.6%
|
|
| 1997 | 9 |
4.6%
|
|
| 1998 | 6 |
3.1%
|
|
| 1999 | 5 |
2.6%
|
|
| 2000 | 10 |
5.1%
|
|
| 2001 | 10 |
5.1%
|
|
| 2002 | 18 |
9.2%
|
|
| 2003 | 16 |
8.2%
|
|
| 2004 | 29 |
14.9%
|
|
| 2005 | 36 |
18.5%
|
|
| 2006 | 29 |
14.9%
|
|
| 2007 | 6 |
3.1%
|
|
| Sysmiss | 254 |