| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 |
15.1%
|
| 1957 | 1 |
1.9%
|
|
| 1975 | 1 |
1.9%
|
|
| 1987 | 1 |
1.9%
|
|
| 1989 | 1 |
1.9%
|
|
| 1990 | 1 |
1.9%
|
|
| 1994 | 1 |
1.9%
|
|
| 1995 | 3 |
5.7%
|
|
| 1997 | 2 |
3.8%
|
|
| 2000 | 2 |
3.8%
|
|
| 2001 | 1 |
1.9%
|
|
| 2002 | 3 |
5.7%
|
|
| 2004 | 1 |
1.9%
|
|
| 2005 | 3 |
5.7%
|
|
| 2006 | 3 |
5.7%
|
|
| 2007 | 1 |
1.9%
|
|
| 2008 | 4 |
7.5%
|
|
| 2009 | 2 |
3.8%
|
|
| 2010 | 1 |
1.9%
|
|
| 2013 | 2 |
3.8%
|
|
| 2015 | 2 |
3.8%
|
|
| 2017 | 1 |
1.9%
|
|
| 2018 | 4 |
7.5%
|
|
| 2019 | 1 |
1.9%
|
|
| 2020 | 2 |
3.8%
|
|
| 2021 | 1 |
1.9%
|
|
| Sysmiss | 325 |