| Year | Count |
|---|---|
| 1975 | 10 |
| 1976 | 5 |
| 1977 | 5 |
| 1978 | 6 |
| 1979 | 7 |
| 1980 | 11 |
| 1981 | 11 |
| 1982 | 20 |
| 1983 | 9 |
| 1984 | 8 |
| 1985 | 12 |
| 1986 | 23 |
| 1987 | 6 |
| 1988 | 91 |
| 1989 | 79 |
| 1990 | 117 |
| 1991 | 90 |
| 1992 | 126 |
| 1993 | 122 |
| 1994 | 148 |
| 1995 | 144 |
| 1996 | 175 |
| 1997 | 162 |
| 1998 | 539 |
| 1999 | 821 |
| 2000 | 733 |
| 2001 | 634 |
| 2002 | 925 |
| 2003 | 5 |
| 2003 | 1,142 |
| 2004 | 7 |
| 2004 | 1,126 |
| 2005 | 1,112 |
| 2006 | 1,151 |
| 2007 | 929 |
| 2008 | 775 |
| 2009 | 781 |
| 2010 | 580 |
| 2011 | 540 |
| 2012 | 499 |
| 2013 | 320 |
| 2014 | 347 |
| 2015 | 321 |
| 2016 | 298 |
| 2017 | 258 |
| 2018 | 190 |
| 2019 | 148 |
| 2020 | 80 |
| 2021 | 91 |
| 2022 | 54 |
| 2023 | 71 |
| 2024 | 56 |