| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 29 |
22.8%
|
| 1948 | 1 |
0.8%
|
|
| 1955 | 1 |
0.8%
|
|
| 1965 | 1 |
0.8%
|
|
| 1970 | 3 |
2.4%
|
|
| 1975 | 1 |
0.8%
|
|
| 1978 | 1 |
0.8%
|
|
| 1980 | 2 |
1.6%
|
|
| 1984 | 1 |
0.8%
|
|
| 1985 | 2 |
1.6%
|
|
| 1987 | 2 |
1.6%
|
|
| 1989 | 2 |
1.6%
|
|
| 1990 | 2 |
1.6%
|
|
| 1993 | 1 |
0.8%
|
|
| 1994 | 3 |
2.4%
|
|
| 1995 | 7 |
5.5%
|
|
| 1997 | 2 |
1.6%
|
|
| 1998 | 3 |
2.4%
|
|
| 2000 | 8 |
6.3%
|
|
| 2001 | 4 |
3.1%
|
|
| 2003 | 4 |
3.1%
|
|
| 2004 | 3 |
2.4%
|
|
| 2005 | 4 |
3.1%
|
|
| 2006 | 1 |
0.8%
|
|
| 2007 | 4 |
3.1%
|
|
| 2008 | 3 |
2.4%
|
|
| 2009 | 2 |
1.6%
|
|
| 2010 | 5 |
3.9%
|
|
| 2011 | 2 |
1.6%
|
|
| 2012 | 5 |
3.9%
|
|
| 2013 | 1 |
0.8%
|
|
| 2014 | 1 |
0.8%
|
|
| 2015 | 4 |
3.1%
|
|
| 2016 | 3 |
2.4%
|
|
| 2017 | 3 |
2.4%
|
|
| 2018 | 1 |
0.8%
|
|
| 2019 | 1 |
0.8%
|
|
| 2021 | 1 |
0.8%
|
|
| 2022 | 3 |
2.4%
|
|
| Sysmiss | 875 |