| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.2%
|
| 1851 | 1 |
0.1%
|
|
| 1889 | 1 |
0.1%
|
|
| 1909 | 1 |
0.1%
|
|
| 1916 | 1 |
0.1%
|
|
| 1919 | 1 |
0.1%
|
|
| 1940 | 1 |
0.1%
|
|
| 1946 | 1 |
0.1%
|
|
| 1948 | 2 |
0.2%
|
|
| 1950 | 1 |
0.1%
|
|
| 1951 | 1 |
0.1%
|
|
| 1960 | 1 |
0.1%
|
|
| 1963 | 2 |
0.2%
|
|
| 1964 | 1 |
0.1%
|
|
| 1972 | 1 |
0.1%
|
|
| 1981 | 1 |
0.1%
|
|
| 1982 | 1 |
0.1%
|
|
| 1984 | 2 |
0.2%
|
|
| 1985 | 2 |
0.2%
|
|
| 1986 | 2 |
0.2%
|
|
| 1987 | 2 |
0.2%
|
|
| 1988 | 2 |
0.2%
|
|
| 1989 | 19 |
2.3%
|
|
| 1990 | 22 |
2.6%
|
|
| 1991 | 48 |
5.8%
|
|
| 1992 | 25 |
3%
|
|
| 1993 | 32 |
3.9%
|
|
| 1994 | 22 |
2.6%
|
|
| 1995 | 33 |
4%
|
|
| 1996 | 25 |
3%
|
|
| 1997 | 36 |
4.3%
|
|
| 1998 | 26 |
3.1%
|
|
| 1999 | 28 |
3.4%
|
|
| 2000 | 32 |
3.9%
|
|
| 2001 | 25 |
3%
|
|
| 2002 | 29 |
3.5%
|
|
| 2003 | 24 |
2.9%
|
|
| 2004 | 12 |
1.4%
|
|
| 2005 | 26 |
3.1%
|
|
| 2006 | 27 |
3.2%
|
|
| 2007 | 16 |
1.9%
|
|
| 2008 | 25 |
3%
|
|
| 2009 | 29 |
3.5%
|
|
| 2010 | 37 |
4.5%
|
|
| 2011 | 25 |
3%
|
|
| 2012 | 16 |
1.9%
|
|
| 2013 | 27 |
3.2%
|
|
| 2014 | 18 |
2.2%
|
|
| 2015 | 18 |
2.2%
|
|
| 2016 | 18 |
2.2%
|
|
| 2017 | 21 |
2.5%
|
|
| 2018 | 13 |
1.6%
|
|
| 2019 | 15 |
1.8%
|
|
| 2020 | 9 |
1.1%
|
|
| 2021 | 14 |
1.7%
|
|
| 2022 | 9 |
1.1%
|