| Year | Count |
|---|---|
| 1960 | 5 |
| 1977 | 5 |
| 1979 | 5 |
| 1981 | 7 |
| 1982 | 6 |
| 1986 | 7 |
| 1988 | 5 |
| 1990 | 6 |
| 1991 | 8 |
| 1992 | 8 |
| 1993 | 8 |
| 1994 | 8 |
| 1995 | 11 |
| 1996 | 9 |
| 1997 | 16 |
| 1998 | 15 |
| 1999 | 16 |
| 2000 | 14 |
| 2001 | 17 |
| 2002 | 22 |
| 2003 | 14 |
| 2004 | 26 |
| 2005 | 33 |
| 2006 | 32 |
| 2007 | 31 |
| 2008 | 38 |
| 2009 | 28 |
| 2010 | 29 |
| 2011 | 37 |
| 2012 | 47 |
| 2013 | 36 |
| 2014 | 28 |
| 2015 | 40 |
| 2016 | 70 |
| 2018 | 58 |
| 2021 | 38 |
| 2022 | 39 |
| 2023 | 47 |
| 2024 | 51 |