| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 81 |
14.3%
|
| 1951 | 1 |
0.2%
|
|
| 1964 | 1 |
0.2%
|
|
| 1965 | 3 |
0.5%
|
|
| 1967 | 2 |
0.4%
|
|
| 1970 | 1 |
0.2%
|
|
| 1973 | 1 |
0.2%
|
|
| 1974 | 1 |
0.2%
|
|
| 1975 | 2 |
0.4%
|
|
| 1976 | 1 |
0.2%
|
|
| 1980 | 7 |
1.2%
|
|
| 1981 | 1 |
0.2%
|
|
| 1984 | 1 |
0.2%
|
|
| 1985 | 5 |
0.9%
|
|
| 1986 | 1 |
0.2%
|
|
| 1987 | 1 |
0.2%
|
|
| 1988 | 5 |
0.9%
|
|
| 1989 | 4 |
0.7%
|
|
| 1990 | 21 |
3.7%
|
|
| 1991 | 1 |
0.2%
|
|
| 1992 | 7 |
1.2%
|
|
| 1993 | 9 |
1.6%
|
|
| 1994 | 5 |
0.9%
|
|
| 1995 | 18 |
3.2%
|
|
| 1996 | 10 |
1.8%
|
|
| 1997 | 13 |
2.3%
|
|
| 1998 | 10 |
1.8%
|
|
| 1999 | 10 |
1.8%
|
|
| 2000 | 37 |
6.5%
|
|
| 2001 | 17 |
3%
|
|
| 2002 | 9 |
1.6%
|
|
| 2003 | 23 |
4.1%
|
|
| 2004 | 9 |
1.6%
|
|
| 2005 | 30 |
5.3%
|
|
| 2006 | 5 |
0.9%
|
|
| 2007 | 15 |
2.6%
|
|
| 2008 | 27 |
4.8%
|
|
| 2009 | 17 |
3%
|
|
| 2010 | 24 |
4.2%
|
|
| 2011 | 19 |
3.4%
|
|
| 2012 | 17 |
3%
|
|
| 2013 | 12 |
2.1%
|
|
| 2014 | 16 |
2.8%
|
|
| 2015 | 25 |
4.4%
|
|
| 2016 | 19 |
3.4%
|
|
| 2017 | 14 |
2.5%
|
|
| 2018 | 9 |
1.6%
|
|
| Sysmiss | 1096 |