| Year | Count |
|---|---|
| 1981 | 5 |
| 1986 | 23 |
| 1987 | 11 |
| 1988 | 22 |
| 1989 | 5 |
| 1990 | 7 |
| 1991 | 15 |
| 1992 | 18 |
| 1993 | 14 |
| 1994 | 31 |
| 1995 | 26 |
| 1996 | 29 |
| 1997 | 42 |
| 1998 | 48 |
| 1999 | 37 |
| 2000 | 65 |
| 2001 | 82 |
| 2002 | 45 |
| 2003 | 33 |
| 2004 | 72 |
| 2005 | 66 |
| 2006 | 73 |
| 2007 | 71 |
| 2008 | 52 |
| 2009 | 49 |
| 2010 | 57 |
| 2011 | 54 |
| 2012 | 74 |
| 2013 | 46 |
| 2014 | 28 |
| 2015 | 46 |
| 2016 | 40 |
| 2017 | 18 |
| 2018 | 13 |
| 2019 | 29 |
| 2020 | 18 |
| 2021 | 11 |
| 2022 | 16 |
| 2023 | 5 |
| 2024 | 7 |