| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 50 |
11.7%
|
| 1949 | 1 |
0.2%
|
|
| 1975 | 1 |
0.2%
|
|
| 1976 | 1 |
0.2%
|
|
| 1984 | 1 |
0.2%
|
|
| 1985 | 1 |
0.2%
|
|
| 1990 | 2 |
0.5%
|
|
| 1991 | 5 |
1.2%
|
|
| 1992 | 4 |
0.9%
|
|
| 1993 | 2 |
0.5%
|
|
| 1994 | 1 |
0.2%
|
|
| 1995 | 9 |
2.1%
|
|
| 1996 | 2 |
0.5%
|
|
| 1997 | 5 |
1.2%
|
|
| 1998 | 4 |
0.9%
|
|
| 1999 | 5 |
1.2%
|
|
| 2000 | 20 |
4.7%
|
|
| 2001 | 9 |
2.1%
|
|
| 2002 | 12 |
2.8%
|
|
| 2003 | 4 |
0.9%
|
|
| 2004 | 14 |
3.3%
|
|
| 2005 | 31 |
7.2%
|
|
| 2006 | 11 |
2.6%
|
|
| 2007 | 9 |
2.1%
|
|
| 2008 | 20 |
4.7%
|
|
| 2009 | 10 |
2.3%
|
|
| 2010 | 35 |
8.2%
|
|
| 2011 | 6 |
1.4%
|
|
| 2012 | 6 |
1.4%
|
|
| 2013 | 7 |
1.6%
|
|
| 2014 | 9 |
2.1%
|
|
| 2015 | 24 |
5.6%
|
|
| 2016 | 13 |
3%
|
|
| 2017 | 12 |
2.8%
|
|
| 2018 | 19 |
4.4%
|
|
| 2019 | 18 |
4.2%
|
|
| 2020 | 26 |
6.1%
|
|
| 2021 | 8 |
1.9%
|
|
| 2022 | 7 |
1.6%
|
|
| 2023 | 5 |
1.2%
|
|
| Sysmiss | 1296 |