| Value | Category | Cases | |
|---|---|---|---|
| 1970 | 1 |
0.3%
|
|
| 1982 | 4 |
1.2%
|
|
| 1983 | 4 |
1.2%
|
|
| 1985 | 7 |
2.1%
|
|
| 1986 | 3 |
0.9%
|
|
| 1987 | 1 |
0.3%
|
|
| 1988 | 3 |
0.9%
|
|
| 1989 | 9 |
2.7%
|
|
| 1990 | 1 |
0.3%
|
|
| 1991 | 11 |
3.3%
|
|
| 1992 | 4 |
1.2%
|
|
| 1994 | 4 |
1.2%
|
|
| 1996 | 4 |
1.2%
|
|
| 1997 | 9 |
2.7%
|
|
| 1998 | 12 |
3.6%
|
|
| 2000 | 21 |
6.3%
|
|
| 2001 | 8 |
2.4%
|
|
| 2002 | 28 |
8.4%
|
|
| 2003 | 15 |
4.5%
|
|
| 2004 | 13 |
3.9%
|
|
| 2005 | 29 |
8.7%
|
|
| 2006 | 21 |
6.3%
|
|
| 2007 | 21 |
6.3%
|
|
| 2008 | 18 |
5.4%
|
|
| 2009 | 17 |
5.1%
|
|
| 2010 | 19 |
5.7%
|
|
| 2011 | 11 |
3.3%
|
|
| 2012 | 8 |
2.4%
|
|
| 2013 | 8 |
2.4%
|
|
| 2014 | 10 |
3%
|
|
| 2015 | 7 |
2.1%
|
|
| 2016 | 2 |
0.6%
|
|
| 2018 | 1 |
0.3%
|