| Year | Count |
|---|---|
| 1988 | 8 |
| 1989 | 7 |
| 1990 | 9 |
| 1991 | 7 |
| 1992 | 9 |
| 1993 | 13 |
| 1994 | 21 |
| 1995 | 31 |
| 1996 | 27 |
| 1997 | 54 |
| 1998 | 56 |
| 1999 | 36 |
| 2000 | 50 |
| 2001 | 54 |
| 2002 | 48 |
| 2003 | 80 |
| 2004 | 126 |
| 2005 | 99 |
| 2006 | 122 |
| 2007 | 117 |
| 2008 | 118 |
| 2009 | 96 |
| 2010 | 135 |
| 2011 | 135 |
| 2012 | 127 |
| 2013 | 133 |
| 2014 | 112 |
| 2015 | 157 |
| 2016 | 173 |
| 2017 | 296 |
| 2018 | 220 |
| 2019 | 229 |
| 2020 | 167 |
| 2021 | 154 |
| 2022 | 124 |
| 2023 | 100 |
| 2024 | 80 |