| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 27 |
7.7%
|
| -7 | Never regiestered (spontaneous) | 0 |
0%
|
| 1937 | 1 |
0.3%
|
|
| 1956 | 1 |
0.3%
|
|
| 1964 | 2 |
0.6%
|
|
| 1967 | 1 |
0.3%
|
|
| 1968 | 1 |
0.3%
|
|
| 1973 | 1 |
0.3%
|
|
| 1974 | 1 |
0.3%
|
|
| 1980 | 1 |
0.3%
|
|
| 1983 | 1 |
0.3%
|
|
| 1985 | 1 |
0.3%
|
|
| 1988 | 1 |
0.3%
|
|
| 1991 | 2 |
0.6%
|
|
| 1992 | 2 |
0.6%
|
|
| 1993 | 2 |
0.6%
|
|
| 1994 | 4 |
1.1%
|
|
| 1995 | 3 |
0.9%
|
|
| 1996 | 3 |
0.9%
|
|
| 1997 | 4 |
1.1%
|
|
| 1998 | 6 |
1.7%
|
|
| 1999 | 5 |
1.4%
|
|
| 2000 | 10 |
2.8%
|
|
| 2001 | 3 |
0.9%
|
|
| 2002 | 12 |
3.4%
|
|
| 2003 | 12 |
3.4%
|
|
| 2004 | 11 |
3.1%
|
|
| 2005 | 12 |
3.4%
|
|
| 2006 | 15 |
4.3%
|
|
| 2007 | 14 |
4%
|
|
| 2008 | 15 |
4.3%
|
|
| 2009 | 24 |
6.8%
|
|
| 2010 | 17 |
4.8%
|
|
| 2011 | 16 |
4.5%
|
|
| 2012 | 17 |
4.8%
|
|
| 2013 | 24 |
6.8%
|
|
| 2014 | 21 |
6%
|
|
| 2015 | 18 |
5.1%
|
|
| 2016 | 14 |
4%
|
|
| 2017 | 25 |
7.1%
|
|
| 2018 | 2 |
0.6%
|