| Year | Count |
|---|---|
| 1987 | 6 |
| 1988 | 7 |
| 1991 | 6 |
| 1992 | 8 |
| 1993 | 7 |
| 1995 | 8 |
| 1996 | 12 |
| 1997 | 11 |
| 1998 | 11 |
| 1999 | 10 |
| 2000 | 13 |
| 2001 | 17 |
| 2002 | 20 |
| 2003 | 20 |
| 2004 | 23 |
| 2005 | 23 |
| 2006 | 30 |
| 2007 | 29 |
| 2008 | 24 |
| 2009 | 31 |
| 2010 | 35 |
| 2011 | 35 |
| 2012 | 40 |
| 2013 | 33 |
| 2014 | 50 |
| 2015 | 53 |
| 2016 | 138 |
| 2017 | 159 |
| 2018 | 53 |
| 2019 | 84 |
| 2020 | 92 |
| 2021 | 112 |
| 2022 | 80 |
| 2023 | 110 |
| 2024 | 80 |