| Year | Count |
|---|---|
| 1991 | 11 |
| 1992 | 10 |
| 1993 | 9 |
| 1994 | 17 |
| 1995 | 19 |
| 1996 | 26 |
| 1997 | 33 |
| 1998 | 31 |
| 1999 | 36 |
| 2000 | 37 |
| 2001 | 56 |
| 2002 | 47 |
| 2003 | 41 |
| 2004 | 39 |
| 2005 | 51 |
| 2006 | 39 |
| 2007 | 49 |
| 2008 | 58 |
| 2009 | 61 |
| 2010 | 59 |
| 2011 | 59 |
| 2012 | 51 |
| 2013 | 51 |
| 2014 | 52 |
| 2015 | 53 |
| 2016 | 135 |
| 2017 | 126 |
| 2018 | 44 |
| 2019 | 76 |
| 2020 | 88 |
| 2021 | 62 |
| 2022 | 66 |
| 2023 | 38 |
| 2024 | 42 |