| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 25 |
23.1%
|
| 1962 | 1 |
0.9%
|
|
| 1973 | 1 |
0.9%
|
|
| 1974 | 1 |
0.9%
|
|
| 1980 | 2 |
1.9%
|
|
| 1982 | 1 |
0.9%
|
|
| 1985 | 3 |
2.8%
|
|
| 1986 | 1 |
0.9%
|
|
| 1987 | 1 |
0.9%
|
|
| 1988 | 1 |
0.9%
|
|
| 1990 | 4 |
3.7%
|
|
| 1993 | 1 |
0.9%
|
|
| 1994 | 1 |
0.9%
|
|
| 1995 | 3 |
2.8%
|
|
| 1996 | 3 |
2.8%
|
|
| 1997 | 2 |
1.9%
|
|
| 1998 | 4 |
3.7%
|
|
| 1999 | 2 |
1.9%
|
|
| 2000 | 8 |
7.4%
|
|
| 2001 | 2 |
1.9%
|
|
| 2002 | 3 |
2.8%
|
|
| 2003 | 2 |
1.9%
|
|
| 2004 | 2 |
1.9%
|
|
| 2005 | 2 |
1.9%
|
|
| 2006 | 1 |
0.9%
|
|
| 2007 | 2 |
1.9%
|
|
| 2008 | 3 |
2.8%
|
|
| 2009 | 1 |
0.9%
|
|
| 2010 | 2 |
1.9%
|
|
| 2012 | 3 |
2.8%
|
|
| 2013 | 1 |
0.9%
|
|
| 2014 | 1 |
0.9%
|
|
| 2015 | 4 |
3.7%
|
|
| 2016 | 2 |
1.9%
|
|
| 2017 | 1 |
0.9%
|
|
| 2018 | 3 |
2.8%
|
|
| 2019 | 2 |
1.9%
|
|
| 2020 | 1 |
0.9%
|
|
| 2021 | 3 |
2.8%
|
|
| 2022 | 2 |
1.9%
|
|
| Sysmiss | 249 |