| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 160 |
4.2%
|
| 1917 | 1 |
0%
|
|
| 1968 | 1 |
0%
|
|
| 1970 | 1 |
0%
|
|
| 1972 | 2 |
0.1%
|
|
| 1973 | 1 |
0%
|
|
| 1975 | 1 |
0%
|
|
| 1976 | 1 |
0%
|
|
| 1977 | 1 |
0%
|
|
| 1978 | 1 |
0%
|
|
| 1980 | 6 |
0.2%
|
|
| 1981 | 1 |
0%
|
|
| 1982 | 3 |
0.1%
|
|
| 1985 | 5 |
0.1%
|
|
| 1986 | 4 |
0.1%
|
|
| 1987 | 1 |
0%
|
|
| 1988 | 5 |
0.1%
|
|
| 1990 | 28 |
0.7%
|
|
| 1991 | 4 |
0.1%
|
|
| 1992 | 17 |
0.5%
|
|
| 1993 | 1 |
0%
|
|
| 1994 | 1 |
0%
|
|
| 1995 | 17 |
0.5%
|
|
| 1996 | 7 |
0.2%
|
|
| 1997 | 7 |
0.2%
|
|
| 1998 | 18 |
0.5%
|
|
| 1999 | 5 |
0.1%
|
|
| 2000 | 77 |
2%
|
|
| 2001 | 17 |
0.5%
|
|
| 2002 | 42 |
1.1%
|
|
| 2003 | 15 |
0.4%
|
|
| 2004 | 24 |
0.6%
|
|
| 2005 | 70 |
1.9%
|
|
| 2006 | 28 |
0.7%
|
|
| 2007 | 35 |
0.9%
|
|
| 2008 | 69 |
1.8%
|
|
| 2009 | 37 |
1%
|
|
| 2010 | 214 |
5.7%
|
|
| 2011 | 39 |
1%
|
|
| 2012 | 188 |
5%
|
|
| 2013 | 54 |
1.4%
|
|
| 2014 | 155 |
4.1%
|
|
| 2015 | 368 |
9.7%
|
|
| 2016 | 185 |
4.9%
|
|
| 2017 | 238 |
6.3%
|
|
| 2018 | 444 |
11.8%
|
|
| 2019 | 343 |
9.1%
|
|
| 2020 | 417 |
11%
|
|
| 2021 | 73 |
1.9%
|
|
| 2022 | 343 |
9.1%
|