Value | Category | Cases | |
---|---|---|---|
-9 | Don't know (spontaneous) | 0 |
0%
|
1931 | 1 |
0.3%
|
|
1936 | 1 |
0.3%
|
|
1937 | 1 |
0.3%
|
|
1953 | 1 |
0.3%
|
|
1961 | 1 |
0.3%
|
|
1964 | 1 |
0.3%
|
|
1967 | 1 |
0.3%
|
|
1968 | 1 |
0.3%
|
|
1977 | 1 |
0.3%
|
|
1986 | 1 |
0.3%
|
|
1987 | 2 |
0.5%
|
|
1988 | 1 |
0.3%
|
|
1989 | 2 |
0.5%
|
|
1990 | 3 |
0.8%
|
|
1991 | 2 |
0.5%
|
|
1992 | 2 |
0.5%
|
|
1993 | 3 |
0.8%
|
|
1994 | 6 |
1.6%
|
|
1995 | 8 |
2.1%
|
|
1996 | 10 |
2.7%
|
|
1997 | 11 |
2.9%
|
|
1998 | 18 |
4.8%
|
|
1999 | 10 |
2.7%
|
|
2000 | 18 |
4.8%
|
|
2001 | 18 |
4.8%
|
|
2002 | 13 |
3.5%
|
|
2003 | 10 |
2.7%
|
|
2004 | 17 |
4.5%
|
|
2005 | 9 |
2.4%
|
|
2006 | 9 |
2.4%
|
|
2007 | 8 |
2.1%
|
|
2008 | 12 |
3.2%
|
|
2009 | 6 |
1.6%
|
|
2010 | 11 |
2.9%
|
|
2011 | 10 |
2.7%
|
|
2012 | 5 |
1.3%
|
|
2013 | 12 |
3.2%
|
|
2014 | 7 |
1.9%
|
|
2015 | 19 |
5.1%
|
|
2016 | 18 |
4.8%
|
|
2017 | 15 |
4%
|
|
2018 | 17 |
4.5%
|
|
2019 | 19 |
5.1%
|
|
2020 | 12 |
3.2%
|
|
2021 | 12 |
3.2%
|
|
2022 | 5 |
1.3%
|
|
2023 | 5 |
1.3%
|