| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 1945 | 1 |
0.1%
|
|
| 1955 | 1 |
0.1%
|
|
| 1957 | 1 |
0.1%
|
|
| 1960 | 2 |
0.2%
|
|
| 1965 | 1 |
0.1%
|
|
| 1966 | 1 |
0.1%
|
|
| 1967 | 1 |
0.1%
|
|
| 1972 | 1 |
0.1%
|
|
| 1975 | 2 |
0.2%
|
|
| 1976 | 2 |
0.2%
|
|
| 1980 | 1 |
0.1%
|
|
| 1990 | 3 |
0.3%
|
|
| 1991 | 1 |
0.1%
|
|
| 1992 | 3 |
0.3%
|
|
| 1993 | 8 |
0.8%
|
|
| 1994 | 7 |
0.7%
|
|
| 1995 | 6 |
0.6%
|
|
| 1996 | 5 |
0.5%
|
|
| 1997 | 5 |
0.5%
|
|
| 1998 | 12 |
1.2%
|
|
| 1999 | 14 |
1.4%
|
|
| 2000 | 24 |
2.3%
|
|
| 2001 | 40 |
3.9%
|
|
| 2002 | 32 |
3.1%
|
|
| 2003 | 42 |
4.1%
|
|
| 2004 | 44 |
4.3%
|
|
| 2005 | 46 |
4.5%
|
|
| 2006 | 54 |
5.3%
|
|
| 2007 | 49 |
4.8%
|
|
| 2008 | 67 |
6.5%
|
|
| 2009 | 52 |
5.1%
|
|
| 2010 | 60 |
5.8%
|
|
| 2011 | 54 |
5.3%
|
|
| 2012 | 29 |
2.8%
|
|
| 2013 | 29 |
2.8%
|
|
| 2014 | 37 |
3.6%
|
|
| 2015 | 62 |
6%
|
|
| 2016 | 54 |
5.3%
|
|
| 2017 | 60 |
5.8%
|
|
| 2018 | 46 |
4.5%
|
|
| 2019 | 38 |
3.7%
|
|
| 2020 | 28 |
2.7%
|
|
| 2021 | 1 |
0.1%
|
|
| 2022 | 2 |
0.2%
|