Value | Category | Cases | |
---|---|---|---|
-9 | Don't know (spontaneous) | 13 |
3.7%
|
1931 | 1 |
0.3%
|
|
1937 | 2 |
0.6%
|
|
1938 | 1 |
0.3%
|
|
1942 | 1 |
0.3%
|
|
1943 | 2 |
0.6%
|
|
1956 | 1 |
0.3%
|
|
1964 | 2 |
0.6%
|
|
1967 | 1 |
0.3%
|
|
1968 | 1 |
0.3%
|
|
1973 | 1 |
0.3%
|
|
1974 | 1 |
0.3%
|
|
1980 | 1 |
0.3%
|
|
1983 | 1 |
0.3%
|
|
1985 | 1 |
0.3%
|
|
1988 | 1 |
0.3%
|
|
1991 | 1 |
0.3%
|
|
1992 | 2 |
0.6%
|
|
1993 | 2 |
0.6%
|
|
1994 | 5 |
1.4%
|
|
1995 | 4 |
1.1%
|
|
1996 | 3 |
0.9%
|
|
1997 | 4 |
1.1%
|
|
1998 | 6 |
1.7%
|
|
1999 | 4 |
1.1%
|
|
2000 | 13 |
3.7%
|
|
2001 | 4 |
1.1%
|
|
2002 | 14 |
4%
|
|
2003 | 13 |
3.7%
|
|
2004 | 14 |
4%
|
|
2005 | 9 |
2.6%
|
|
2006 | 16 |
4.5%
|
|
2007 | 13 |
3.7%
|
|
2008 | 16 |
4.5%
|
|
2009 | 23 |
6.5%
|
|
2010 | 15 |
4.3%
|
|
2011 | 19 |
5.4%
|
|
2012 | 17 |
4.8%
|
|
2013 | 23 |
6.5%
|
|
2014 | 24 |
6.8%
|
|
2015 | 22 |
6.3%
|
|
2016 | 14 |
4%
|
|
2017 | 21 |
6%
|