| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.5%
|
| -7 | Never regiestered (spontaneous) | 0 |
0%
|
| 1952 | 1 |
0.3%
|
|
| 1954 | 1 |
0.3%
|
|
| 1969 | 1 |
0.3%
|
|
| 1970 | 1 |
0.3%
|
|
| 1973 | 1 |
0.3%
|
|
| 1974 | 1 |
0.3%
|
|
| 1975 | 1 |
0.3%
|
|
| 1976 | 1 |
0.3%
|
|
| 1978 | 1 |
0.3%
|
|
| 1981 | 1 |
0.3%
|
|
| 1983 | 1 |
0.3%
|
|
| 1986 | 2 |
0.5%
|
|
| 1987 | 2 |
0.5%
|
|
| 1988 | 1 |
0.3%
|
|
| 1990 | 3 |
0.8%
|
|
| 1991 | 2 |
0.5%
|
|
| 1992 | 3 |
0.8%
|
|
| 1993 | 1 |
0.3%
|
|
| 1994 | 2 |
0.5%
|
|
| 1995 | 1 |
0.3%
|
|
| 1996 | 2 |
0.5%
|
|
| 1997 | 1 |
0.3%
|
|
| 1998 | 5 |
1.4%
|
|
| 1999 | 3 |
0.8%
|
|
| 2000 | 7 |
1.9%
|
|
| 2001 | 9 |
2.5%
|
|
| 2002 | 13 |
3.6%
|
|
| 2003 | 7 |
1.9%
|
|
| 2004 | 6 |
1.6%
|
|
| 2005 | 9 |
2.5%
|
|
| 2006 | 9 |
2.5%
|
|
| 2007 | 6 |
1.6%
|
|
| 2008 | 10 |
2.7%
|
|
| 2009 | 9 |
2.5%
|
|
| 2010 | 14 |
3.8%
|
|
| 2011 | 9 |
2.5%
|
|
| 2012 | 15 |
4.1%
|
|
| 2013 | 19 |
5.2%
|
|
| 2014 | 23 |
6.3%
|
|
| 2015 | 26 |
7.1%
|
|
| 2016 | 25 |
6.8%
|
|
| 2017 | 26 |
7.1%
|
|
| 2018 | 21 |
5.8%
|
|
| 2019 | 27 |
7.4%
|
|
| 2020 | 13 |
3.6%
|
|
| 2021 | 11 |
3%
|
|
| 2022 | 8 |
2.2%
|
|
| 2023 | 2 |
0.5%
|