| Year | Count |
|---|---|
| 1956 | 5 |
| 1957 | 10 |
| 1960 | 5 |
| 1962 | 10 |
| 1964 | 12 |
| 1966 | 10 |
| 1971 | 6 |
| 1973 | 17 |
| 1978 | 25 |
| 1980 | 12 |
| 1981 | 29 |
| 1982 | 7 |
| 1984 | 16 |
| 1985 | 16 |
| 1986 | 14 |
| 1987 | 26 |
| 1988 | 15 |
| 1991 | 29 |
| 1992 | 34 |
| 1993 | 36 |
| 1994 | 6 |
| 1995 | 30 |
| 1996 | 49 |
| 1997 | 82 |
| 1998 | 93 |
| 1999 | 73 |
| 2000 | 80 |
| 2001 | 97 |
| 2002 | 92 |
| 2003 | 120 |
| 2004 | 222 |
| 2005 | 215 |
| 2006 | 174 |
| 2007 | 149 |
| 2008 | 151 |
| 2009 | 112 |
| 2010 | 86 |
| 2011 | 102 |
| 2012 | 80 |
| 2013 | 55 |
| 2014 | 65 |
| 2015 | 48 |
| 2016 | 47 |
| 2017 | 24 |
| 2018 | 53 |
| 2019 | 41 |
| 2020 | 39 |
| 2021 | 24 |
| 2022 | 25 |
| 2023 | 52 |
| 2024 | 23 |