| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 21 |
1.5%
|
| 1936 | 1 |
0.1%
|
|
| 1937 | 1 |
0.1%
|
|
| 1941 | 2 |
0.1%
|
|
| 1942 | 1 |
0.1%
|
|
| 1954 | 2 |
0.1%
|
|
| 1956 | 1 |
0.1%
|
|
| 1958 | 1 |
0.1%
|
|
| 1960 | 1 |
0.1%
|
|
| 1964 | 1 |
0.1%
|
|
| 1965 | 1 |
0.1%
|
|
| 1966 | 3 |
0.2%
|
|
| 1967 | 2 |
0.1%
|
|
| 1968 | 1 |
0.1%
|
|
| 1969 | 2 |
0.1%
|
|
| 1974 | 1 |
0.1%
|
|
| 1975 | 1 |
0.1%
|
|
| 1982 | 1 |
0.1%
|
|
| 1985 | 2 |
0.1%
|
|
| 1987 | 2 |
0.1%
|
|
| 1989 | 3 |
0.2%
|
|
| 1990 | 1 |
0.1%
|
|
| 1991 | 12 |
0.8%
|
|
| 1992 | 16 |
1.1%
|
|
| 1993 | 19 |
1.3%
|
|
| 1994 | 12 |
0.8%
|
|
| 1995 | 16 |
1.1%
|
|
| 1996 | 18 |
1.2%
|
|
| 1997 | 15 |
1%
|
|
| 1998 | 30 |
2.1%
|
|
| 1999 | 34 |
2.4%
|
|
| 2000 | 51 |
3.5%
|
|
| 2001 | 41 |
2.8%
|
|
| 2002 | 50 |
3.5%
|
|
| 2003 | 52 |
3.6%
|
|
| 2004 | 48 |
3.3%
|
|
| 2005 | 63 |
4.4%
|
|
| 2006 | 59 |
4.1%
|
|
| 2007 | 59 |
4.1%
|
|
| 2008 | 59 |
4.1%
|
|
| 2009 | 77 |
5.3%
|
|
| 2010 | 94 |
6.5%
|
|
| 2011 | 64 |
4.4%
|
|
| 2012 | 75 |
5.2%
|
|
| 2013 | 75 |
5.2%
|
|
| 2014 | 87 |
6%
|
|
| 2015 | 80 |
5.5%
|
|
| 2016 | 89 |
6.2%
|
|
| 2017 | 99 |
6.8%
|