| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 151 |
40.4%
|
| 1956 | 1 |
0.3%
|
|
| 1957 | 1 |
0.3%
|
|
| 1967 | 1 |
0.3%
|
|
| 1970 | 1 |
0.3%
|
|
| 1971 | 2 |
0.5%
|
|
| 1976 | 1 |
0.3%
|
|
| 1980 | 3 |
0.8%
|
|
| 1982 | 1 |
0.3%
|
|
| 1985 | 3 |
0.8%
|
|
| 1987 | 1 |
0.3%
|
|
| 1988 | 1 |
0.3%
|
|
| 1990 | 3 |
0.8%
|
|
| 1991 | 3 |
0.8%
|
|
| 1992 | 1 |
0.3%
|
|
| 1995 | 4 |
1.1%
|
|
| 1996 | 2 |
0.5%
|
|
| 1998 | 2 |
0.5%
|
|
| 1999 | 3 |
0.8%
|
|
| 2000 | 6 |
1.6%
|
|
| 2001 | 1 |
0.3%
|
|
| 2002 | 4 |
1.1%
|
|
| 2003 | 1 |
0.3%
|
|
| 2004 | 7 |
1.9%
|
|
| 2005 | 11 |
2.9%
|
|
| 2006 | 1 |
0.3%
|
|
| 2007 | 2 |
0.5%
|
|
| 2008 | 9 |
2.4%
|
|
| 2009 | 6 |
1.6%
|
|
| 2010 | 10 |
2.7%
|
|
| 2011 | 12 |
3.2%
|
|
| 2012 | 5 |
1.3%
|
|
| 2013 | 5 |
1.3%
|
|
| 2014 | 8 |
2.1%
|
|
| 2015 | 25 |
6.7%
|
|
| 2016 | 11 |
2.9%
|
|
| 2017 | 10 |
2.7%
|
|
| 2018 | 26 |
7%
|
|
| 2019 | 17 |
4.5%
|
|
| 2020 | 8 |
2.1%
|
|
| 2021 | 4 |
1.1%
|
|
| Sysmiss | 1199 |