| Year | Count |
|---|---|
| 1979 | 5 |
| 1986 | 6 |
| 1987 | 8 |
| 1988 | 6 |
| 1989 | 16 |
| 1990 | 19 |
| 1991 | 27 |
| 1992 | 54 |
| 1993 | 34 |
| 1994 | 29 |
| 1995 | 12 |
| 1996 | 42 |
| 1997 | 43 |
| 1998 | 48 |
| 1999 | 27 |
| 2000 | 72 |
| 2001 | 133 |
| 2002 | 75 |
| 2003 | 88 |
| 2004 | 80 |
| 2005 | 86 |
| 2006 | 95 |
| 2007 | 97 |
| 2008 | 69 |
| 2009 | 56 |
| 2010 | 281 |
| 2011 | 186 |
| 2012 | 157 |
| 2013 | 110 |
| 2014 | 123 |
| 2015 | 149 |
| 2016 | 129 |
| 2017 | 104 |
| 2018 | 82 |
| 2019 | 80 |
| 2020 | 66 |
| 2021 | 47 |
| 2022 | 42 |
| 2023 | 40 |
| 2024 | 28 |