| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 27 |
9.5%
|
| 1873 | 1 |
0.4%
|
|
| 1881 | 1 |
0.4%
|
|
| 1930 | 1 |
0.4%
|
|
| 1958 | 1 |
0.4%
|
|
| 1960 | 3 |
1.1%
|
|
| 1970 | 1 |
0.4%
|
|
| 1974 | 1 |
0.4%
|
|
| 1975 | 3 |
1.1%
|
|
| 1976 | 1 |
0.4%
|
|
| 1977 | 1 |
0.4%
|
|
| 1980 | 1 |
0.4%
|
|
| 1981 | 1 |
0.4%
|
|
| 1983 | 1 |
0.4%
|
|
| 1985 | 2 |
0.7%
|
|
| 1986 | 2 |
0.7%
|
|
| 1987 | 1 |
0.4%
|
|
| 1989 | 4 |
1.4%
|
|
| 1990 | 10 |
3.5%
|
|
| 1991 | 18 |
6.4%
|
|
| 1992 | 8 |
2.8%
|
|
| 1993 | 6 |
2.1%
|
|
| 1994 | 6 |
2.1%
|
|
| 1995 | 11 |
3.9%
|
|
| 1996 | 12 |
4.2%
|
|
| 1997 | 4 |
1.4%
|
|
| 1998 | 6 |
2.1%
|
|
| 1999 | 4 |
1.4%
|
|
| 2000 | 12 |
4.2%
|
|
| 2001 | 4 |
1.4%
|
|
| 2002 | 2 |
0.7%
|
|
| 2003 | 9 |
3.2%
|
|
| 2004 | 9 |
3.2%
|
|
| 2005 | 8 |
2.8%
|
|
| 2006 | 4 |
1.4%
|
|
| 2007 | 6 |
2.1%
|
|
| 2008 | 6 |
2.1%
|
|
| 2009 | 10 |
3.5%
|
|
| 2010 | 12 |
4.2%
|
|
| 2011 | 9 |
3.2%
|
|
| 2012 | 14 |
4.9%
|
|
| 2013 | 8 |
2.8%
|
|
| 2014 | 12 |
4.2%
|
|
| 2015 | 5 |
1.8%
|
|
| 2016 | 8 |
2.8%
|
|
| 2017 | 3 |
1.1%
|
|
| 2018 | 4 |
1.4%
|
|
| Sysmiss | 126 |