| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1.3%
|
| 1906 | 1 |
0.7%
|
|
| 1947 | 1 |
0.7%
|
|
| 1951 | 1 |
0.7%
|
|
| 1966 | 1 |
0.7%
|
|
| 1969 | 1 |
0.7%
|
|
| 1974 | 2 |
1.3%
|
|
| 1982 | 1 |
0.7%
|
|
| 1984 | 1 |
0.7%
|
|
| 1986 | 1 |
0.7%
|
|
| 1988 | 2 |
1.3%
|
|
| 1989 | 2 |
1.3%
|
|
| 1990 | 6 |
4%
|
|
| 1991 | 7 |
4.6%
|
|
| 1992 | 8 |
5.3%
|
|
| 1993 | 2 |
1.3%
|
|
| 1994 | 3 |
2%
|
|
| 1995 | 3 |
2%
|
|
| 1996 | 4 |
2.6%
|
|
| 1997 | 5 |
3.3%
|
|
| 1998 | 4 |
2.6%
|
|
| 1999 | 2 |
1.3%
|
|
| 2000 | 4 |
2.6%
|
|
| 2001 | 4 |
2.6%
|
|
| 2002 | 17 |
11.3%
|
|
| 2003 | 7 |
4.6%
|
|
| 2004 | 4 |
2.6%
|
|
| 2005 | 6 |
4%
|
|
| 2006 | 7 |
4.6%
|
|
| 2007 | 10 |
6.6%
|
|
| 2008 | 2 |
1.3%
|
|
| 2009 | 6 |
4%
|
|
| 2010 | 4 |
2.6%
|
|
| 2011 | 2 |
1.3%
|
|
| 2013 | 4 |
2.6%
|
|
| 2014 | 1 |
0.7%
|
|
| 2015 | 6 |
4%
|
|
| 2016 | 3 |
2%
|
|
| 2017 | 2 |
1.3%
|
|
| 2019 | 1 |
0.7%
|
|
| 2020 | 1 |
0.7%
|