| Year | Count |
|---|---|
| 1988 | 20 |
| 1990 | 38 |
| 1991 | 12 |
| 1993 | 10 |
| 1994 | 78 |
| 1995 | 37 |
| 1996 | 98 |
| 1997 | 104 |
| 1998 | 133 |
| 1999 | 139 |
| 2000 | 118 |
| 2001 | 157 |
| 2002 | 131 |
| 2003 | 141 |
| 2004 | 180 |
| 2005 | 264 |
| 2006 | 255 |
| 2007 | 279 |
| 2008 | 743 |
| 2009 | 1,372 |
| 2010 | 583 |
| 2011 | 815 |
| 2012 | 733 |
| 2013 | 497 |
| 2014 | 400 |
| 2015 | 385 |
| 2016 | 286 |
| 2017 | 308 |
| 2018 | 188 |
| 2019 | 163 |
| 2020 | 186 |
| 2021 | 157 |
| 2022 | 137 |
| 2023 | 83 |
| 2024 | 51 |