| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| 1842 | 1 |
0.3%
|
|
| 1855 | 1 |
0.3%
|
|
| 1867 | 1 |
0.3%
|
|
| 1883 | 1 |
0.3%
|
|
| 1885 | 1 |
0.3%
|
|
| 1891 | 1 |
0.3%
|
|
| 1904 | 1 |
0.3%
|
|
| 1905 | 1 |
0.3%
|
|
| 1907 | 1 |
0.3%
|
|
| 1913 | 1 |
0.3%
|
|
| 1917 | 1 |
0.3%
|
|
| 1918 | 1 |
0.3%
|
|
| 1921 | 3 |
0.9%
|
|
| 1923 | 1 |
0.3%
|
|
| 1925 | 2 |
0.6%
|
|
| 1927 | 1 |
0.3%
|
|
| 1928 | 2 |
0.6%
|
|
| 1929 | 1 |
0.3%
|
|
| 1932 | 1 |
0.3%
|
|
| 1933 | 1 |
0.3%
|
|
| 1937 | 1 |
0.3%
|
|
| 1938 | 1 |
0.3%
|
|
| 1939 | 1 |
0.3%
|
|
| 1941 | 1 |
0.3%
|
|
| 1945 | 1 |
0.3%
|
|
| 1946 | 2 |
0.6%
|
|
| 1947 | 1 |
0.3%
|
|
| 1948 | 2 |
0.6%
|
|
| 1954 | 2 |
0.6%
|
|
| 1955 | 1 |
0.3%
|
|
| 1956 | 1 |
0.3%
|
|
| 1958 | 1 |
0.3%
|
|
| 1960 | 2 |
0.6%
|
|
| 1961 | 2 |
0.6%
|
|
| 1962 | 3 |
0.9%
|
|
| 1963 | 2 |
0.6%
|
|
| 1964 | 2 |
0.6%
|
|
| 1965 | 2 |
0.6%
|
|
| 1967 | 1 |
0.3%
|
|
| 1968 | 3 |
0.9%
|
|
| 1970 | 2 |
0.6%
|
|
| 1971 | 2 |
0.6%
|
|
| 1972 | 1 |
0.3%
|
|
| 1973 | 2 |
0.6%
|
|
| 1974 | 3 |
0.9%
|
|
| 1975 | 1 |
0.3%
|
|
| 1976 | 3 |
0.9%
|
|
| 1977 | 1 |
0.3%
|
|
| 1978 | 3 |
0.9%
|
|
| 1979 | 1 |
0.3%
|
|
| 1980 | 5 |
1.6%
|
|
| 1981 | 1 |
0.3%
|
|
| 1982 | 1 |
0.3%
|
|
| 1983 | 5 |
1.6%
|
|
| 1984 | 6 |
1.9%
|
|
| 1985 | 5 |
1.6%
|
|
| 1986 | 2 |
0.6%
|
|
| 1987 | 5 |
1.6%
|
|
| 1988 | 4 |
1.3%
|
|
| 1989 | 9 |
2.8%
|
|
| 1990 | 7 |
2.2%
|
|
| 1991 | 5 |
1.6%
|
|
| 1992 | 4 |
1.3%
|
|
| 1993 | 6 |
1.9%
|
|
| 1994 | 8 |
2.5%
|
|
| 1995 | 12 |
3.8%
|
|
| 1996 | 8 |
2.5%
|
|
| 1998 | 2 |
0.6%
|
|
| 1999 | 5 |
1.6%
|
|
| 2000 | 7 |
2.2%
|
|
| 2001 | 4 |
1.3%
|
|
| 2002 | 8 |
2.5%
|
|
| 2003 | 8 |
2.5%
|
|
| 2004 | 8 |
2.5%
|
|
| 2005 | 5 |
1.6%
|
|
| 2006 | 8 |
2.5%
|
|
| 2007 | 5 |
1.6%
|
|
| 2008 | 6 |
1.9%
|
|
| 2009 | 4 |
1.3%
|
|
| 2010 | 11 |
3.4%
|
|
| 2011 | 7 |
2.2%
|
|
| 2012 | 8 |
2.5%
|
|
| 2013 | 3 |
0.9%
|
|
| 2014 | 2 |
0.6%
|
|
| 2015 | 10 |
3.1%
|
|
| 2016 | 3 |
0.9%
|
|
| 2017 | 10 |
3.1%
|
|
| 2018 | 7 |
2.2%
|
|
| 2019 | 6 |
1.9%
|
|
| 2020 | 6 |
1.9%
|
|
| 2021 | 6 |
1.9%
|
|
| 2023 | 1 |
0.3%
|