| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 34 |
25.8%
|
| 1949 | 1 |
0.8%
|
|
| 1965 | 1 |
0.8%
|
|
| 1966 | 1 |
0.8%
|
|
| 1980 | 1 |
0.8%
|
|
| 1985 | 1 |
0.8%
|
|
| 1986 | 2 |
1.5%
|
|
| 1991 | 1 |
0.8%
|
|
| 1995 | 2 |
1.5%
|
|
| 1996 | 1 |
0.8%
|
|
| 1997 | 1 |
0.8%
|
|
| 2000 | 6 |
4.5%
|
|
| 2001 | 1 |
0.8%
|
|
| 2002 | 2 |
1.5%
|
|
| 2003 | 2 |
1.5%
|
|
| 2004 | 1 |
0.8%
|
|
| 2005 | 4 |
3%
|
|
| 2007 | 3 |
2.3%
|
|
| 2008 | 5 |
3.8%
|
|
| 2009 | 3 |
2.3%
|
|
| 2010 | 3 |
2.3%
|
|
| 2011 | 4 |
3%
|
|
| 2012 | 8 |
6.1%
|
|
| 2013 | 5 |
3.8%
|
|
| 2014 | 6 |
4.5%
|
|
| 2015 | 7 |
5.3%
|
|
| 2016 | 7 |
5.3%
|
|
| 2017 | 9 |
6.8%
|
|
| 2018 | 4 |
3%
|
|
| 2019 | 6 |
4.5%
|
|
| Sysmiss | 469 |