Value | Category | Cases | |
---|---|---|---|
-9 | Don't know (spontaneous) | 0 |
0%
|
1823 | 1 |
0.4%
|
|
1886 | 1 |
0.4%
|
|
1904 | 1 |
0.4%
|
|
1922 | 1 |
0.4%
|
|
1927 | 1 |
0.4%
|
|
1943 | 1 |
0.4%
|
|
1946 | 1 |
0.4%
|
|
1947 | 1 |
0.4%
|
|
1948 | 1 |
0.4%
|
|
1955 | 1 |
0.4%
|
|
1956 | 1 |
0.4%
|
|
1957 | 2 |
0.8%
|
|
1958 | 2 |
0.8%
|
|
1960 | 3 |
1.3%
|
|
1963 | 1 |
0.4%
|
|
1965 | 1 |
0.4%
|
|
1966 | 1 |
0.4%
|
|
1967 | 2 |
0.8%
|
|
1970 | 2 |
0.8%
|
|
1972 | 3 |
1.3%
|
|
1973 | 2 |
0.8%
|
|
1975 | 2 |
0.8%
|
|
1976 | 2 |
0.8%
|
|
1977 | 5 |
2.1%
|
|
1978 | 6 |
2.5%
|
|
1979 | 5 |
2.1%
|
|
1980 | 7 |
2.9%
|
|
1981 | 6 |
2.5%
|
|
1982 | 7 |
2.9%
|
|
1983 | 6 |
2.5%
|
|
1984 | 8 |
3.3%
|
|
1985 | 6 |
2.5%
|
|
1986 | 3 |
1.3%
|
|
1987 | 5 |
2.1%
|
|
1988 | 3 |
1.3%
|
|
1989 | 10 |
4.2%
|
|
1990 | 4 |
1.7%
|
|
1991 | 8 |
3.3%
|
|
1992 | 11 |
4.6%
|
|
1993 | 8 |
3.3%
|
|
1994 | 3 |
1.3%
|
|
1995 | 6 |
2.5%
|
|
1996 | 6 |
2.5%
|
|
1997 | 5 |
2.1%
|
|
1998 | 6 |
2.5%
|
|
1999 | 9 |
3.8%
|
|
2000 | 7 |
2.9%
|
|
2001 | 8 |
3.3%
|
|
2002 | 4 |
1.7%
|
|
2003 | 4 |
1.7%
|
|
2004 | 4 |
1.7%
|
|
2005 | 3 |
1.3%
|
|
2006 | 7 |
2.9%
|
|
2007 | 4 |
1.7%
|
|
2008 | 2 |
0.8%
|
|
2009 | 2 |
0.8%
|
|
2010 | 6 |
2.5%
|
|
2011 | 1 |
0.4%
|
|
2012 | 1 |
0.4%
|
|
2013 | 1 |
0.4%
|
|
2015 | 4 |
1.7%
|
|
2016 | 1 |
0.4%
|
|
2017 | 4 |
1.7%
|