| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 50 |
25.8%
|
| 1930 | 1 |
0.5%
|
|
| 1950 | 2 |
1%
|
|
| 1958 | 1 |
0.5%
|
|
| 1960 | 1 |
0.5%
|
|
| 1970 | 1 |
0.5%
|
|
| 1974 | 1 |
0.5%
|
|
| 1978 | 2 |
1%
|
|
| 1980 | 2 |
1%
|
|
| 1982 | 1 |
0.5%
|
|
| 1987 | 1 |
0.5%
|
|
| 1990 | 6 |
3.1%
|
|
| 1992 | 3 |
1.5%
|
|
| 1995 | 1 |
0.5%
|
|
| 1996 | 2 |
1%
|
|
| 1997 | 1 |
0.5%
|
|
| 1998 | 3 |
1.5%
|
|
| 1999 | 2 |
1%
|
|
| 2000 | 6 |
3.1%
|
|
| 2001 | 1 |
0.5%
|
|
| 2002 | 3 |
1.5%
|
|
| 2003 | 1 |
0.5%
|
|
| 2004 | 3 |
1.5%
|
|
| 2005 | 3 |
1.5%
|
|
| 2006 | 5 |
2.6%
|
|
| 2007 | 4 |
2.1%
|
|
| 2008 | 3 |
1.5%
|
|
| 2009 | 3 |
1.5%
|
|
| 2010 | 8 |
4.1%
|
|
| 2011 | 5 |
2.6%
|
|
| 2012 | 9 |
4.6%
|
|
| 2013 | 3 |
1.5%
|
|
| 2014 | 9 |
4.6%
|
|
| 2015 | 6 |
3.1%
|
|
| 2016 | 7 |
3.6%
|
|
| 2017 | 4 |
2.1%
|
|
| 2018 | 11 |
5.7%
|
|
| 2019 | 7 |
3.6%
|
|
| 2020 | 8 |
4.1%
|
|
| 2021 | 3 |
1.5%
|
|
| 2022 | 1 |
0.5%
|
|
| Sysmiss | 404 |