| Year | Count |
|---|---|
| 1968 | 5 |
| 1986 | 5 |
| 1988 | 6 |
| 1989 | 7 |
| 1990 | 7 |
| 1991 | 8 |
| 1992 | 5 |
| 1994 | 8 |
| 1995 | 5 |
| 1996 | 11 |
| 1997 | 22 |
| 1998 | 14 |
| 1999 | 18 |
| 2000 | 23 |
| 2001 | 32 |
| 2002 | 26 |
| 2003 | 30 |
| 2004 | 45 |
| 2005 | 35 |
| 2006 | 39 |
| 2007 | 48 |
| 2008 | 34 |
| 2009 | 28 |
| 2010 | 34 |
| 2011 | 31 |
| 2012 | 28 |
| 2013 | 38 |
| 2014 | 22 |
| 2015 | 27 |
| 2016 | 51 |
| 2017 | 48 |
| 2018 | 32 |
| 2019 | 30 |
| 2020 | 34 |
| 2021 | 40 |
| 2022 | 14 |
| 2023 | 20 |
| 2024 | 20 |