Value | Category | Cases | |
---|---|---|---|
-9 | Don't know (spontaneous) | 1 |
0.3%
|
1855 | 1 |
0.3%
|
|
1909 | 1 |
0.3%
|
|
1920 | 1 |
0.3%
|
|
1927 | 1 |
0.3%
|
|
1951 | 3 |
0.8%
|
|
1953 | 2 |
0.6%
|
|
1955 | 1 |
0.3%
|
|
1956 | 1 |
0.3%
|
|
1958 | 4 |
1.1%
|
|
1959 | 1 |
0.3%
|
|
1960 | 1 |
0.3%
|
|
1961 | 3 |
0.8%
|
|
1962 | 2 |
0.6%
|
|
1963 | 3 |
0.8%
|
|
1966 | 1 |
0.3%
|
|
1974 | 1 |
0.3%
|
|
1977 | 2 |
0.6%
|
|
1980 | 2 |
0.6%
|
|
1981 | 1 |
0.3%
|
|
1982 | 1 |
0.3%
|
|
1983 | 1 |
0.3%
|
|
1984 | 1 |
0.3%
|
|
1987 | 3 |
0.8%
|
|
1988 | 2 |
0.6%
|
|
1989 | 4 |
1.1%
|
|
1990 | 22 |
6.1%
|
|
1991 | 19 |
5.3%
|
|
1992 | 24 |
6.6%
|
|
1993 | 18 |
5%
|
|
1994 | 9 |
2.5%
|
|
1995 | 7 |
1.9%
|
|
1996 | 13 |
3.6%
|
|
1997 | 11 |
3%
|
|
1998 | 10 |
2.8%
|
|
1999 | 8 |
2.2%
|
|
2000 | 13 |
3.6%
|
|
2001 | 8 |
2.2%
|
|
2002 | 13 |
3.6%
|
|
2003 | 11 |
3%
|
|
2004 | 9 |
2.5%
|
|
2005 | 12 |
3.3%
|
|
2006 | 9 |
2.5%
|
|
2007 | 19 |
5.3%
|
|
2008 | 7 |
1.9%
|
|
2009 | 9 |
2.5%
|
|
2010 | 13 |
3.6%
|
|
2011 | 14 |
3.9%
|
|
2012 | 8 |
2.2%
|
|
2013 | 8 |
2.2%
|
|
2014 | 5 |
1.4%
|
|
2015 | 8 |
2.2%
|
|
2016 | 3 |
0.8%
|
|
2017 | 6 |
1.7%
|