| Year | Count |
|---|---|
| 1968 | 6 |
| 1972 | 9 |
| 1975 | 11 |
| 1976 | 14 |
| 1979 | 10 |
| 1982 | 6 |
| 1984 | 7 |
| 1985 | 11 |
| 1986 | 9 |
| 1987 | 17 |
| 1988 | 13 |
| 1989 | 16 |
| 1990 | 21 |
| 1991 | 23 |
| 1992 | 22 |
| 1993 | 40 |
| 1994 | 47 |
| 1995 | 64 |
| 1996 | 61 |
| 1997 | 64 |
| 1998 | 81 |
| 1999 | 97 |
| 2000 | 98 |
| 2001 | 99 |
| 2002 | 103 |
| 2003 | 119 |
| 2004 | 116 |
| 2005 | 117 |
| 2006 | 122 |
| 2007 | 109 |
| 2008 | 103 |
| 2009 | 113 |
| 2010 | 132 |
| 2011 | 82 |
| 2012 | 110 |
| 2013 | 102 |
| 2014 | 102 |
| 2015 | 106 |
| 2016 | 231 |
| 2017 | 294 |
| 2018 | 120 |
| 2019 | 148 |
| 2020 | 114 |
| 2021 | 130 |
| 2022 | 122 |
| 2023 | 118 |
| 2024 | 94 |