| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| 1975 | 1 |
0.3%
|
|
| 1986 | 1 |
0.3%
|
|
| 1989 | 1 |
0.3%
|
|
| 1990 | 1 |
0.3%
|
|
| 1991 | 2 |
0.6%
|
|
| 1992 | 2 |
0.6%
|
|
| 1993 | 5 |
1.6%
|
|
| 1994 | 3 |
0.9%
|
|
| 1995 | 3 |
0.9%
|
|
| 1996 | 2 |
0.6%
|
|
| 1997 | 6 |
1.9%
|
|
| 1998 | 2 |
0.6%
|
|
| 1999 | 3 |
0.9%
|
|
| 2000 | 11 |
3.4%
|
|
| 2001 | 3 |
0.9%
|
|
| 2002 | 11 |
3.4%
|
|
| 2003 | 6 |
1.9%
|
|
| 2004 | 2 |
0.6%
|
|
| 2005 | 10 |
3.1%
|
|
| 2006 | 6 |
1.9%
|
|
| 2007 | 13 |
4%
|
|
| 2008 | 19 |
5.9%
|
|
| 2009 | 5 |
1.6%
|
|
| 2010 | 21 |
6.5%
|
|
| 2011 | 7 |
2.2%
|
|
| 2012 | 16 |
5%
|
|
| 2013 | 23 |
7.1%
|
|
| 2014 | 25 |
7.8%
|
|
| 2015 | 31 |
9.6%
|
|
| 2016 | 28 |
8.7%
|
|
| 2017 | 27 |
8.4%
|
|
| 2018 | 18 |
5.6%
|
|
| 2019 | 5 |
1.6%
|
|
| 2020 | 2 |
0.6%
|
|
| Sysmiss | 250 |