| Year | Count |
|---|---|
| 1978 | 7 |
| 1979 | 6 |
| 1980 | 5 |
| 1981 | 8 |
| 1982 | 12 |
| 1983 | 8 |
| 1987 | 7 |
| 1988 | 11 |
| 1989 | 13 |
| 1991 | 10 |
| 1992 | 20 |
| 1993 | 12 |
| 1994 | 15 |
| 1995 | 17 |
| 1996 | 36 |
| 1997 | 25 |
| 1998 | 30 |
| 1999 | 32 |
| 2000 | 16 |
| 2001 | 53 |
| 2002 | 82 |
| 2003 | 78 |
| 2004 | 60 |
| 2005 | 55 |
| 2006 | 50 |
| 2007 | 42 |
| 2008 | 50 |
| 2009 | 69 |
| 2010 | 50 |
| 2011 | 30 |
| 2012 | 18 |
| 2013 | 15 |
| 2014 | 21 |
| 2015 | 20 |
| 2016 | 9 |
| 2017 | 5 |
| 2018 | 55 |
| 2019 | 47 |
| 2020 | 44 |
| 2021 | 67 |
| 2022 | 51 |
| 2023 | 41 |
| 2024 | 38 |