| Year | Count |
|---|---|
| 1961 | 8 |
| 1970 | 6 |
| 1974 | 5 |
| 1976 | 27 |
| 1977 | 31 |
| 1978 | 23 |
| 1979 | 36 |
| 1980 | 7 |
| 1981 | 15 |
| 1982 | 20 |
| 1983 | 22 |
| 1984 | 33 |
| 1985 | 43 |
| 1986 | 29 |
| 1987 | 48 |
| 1988 | 64 |
| 1989 | 65 |
| 1990 | 45 |
| 1991 | 105 |
| 1992 | 76 |
| 1993 | 60 |
| 1994 | 93 |
| 1995 | 81 |
| 1996 | 86 |
| 1997 | 108 |
| 1998 | 128 |
| 1999 | 64 |
| 2000 | 77 |
| 2001 | 97 |
| 2002 | 98 |
| 2003 | 80 |
| 2004 | 196 |
| 2005 | 178 |
| 2006 | 174 |
| 2007 | 170 |
| 2008 | 170 |
| 2009 | 115 |
| 2010 | 114 |
| 2011 | 109 |
| 2012 | 90 |
| 2013 | 117 |
| 2014 | 63 |
| 2015 | 134 |
| 2016 | 147 |
| 2017 | 105 |
| 2018 | 64 |
| 2019 | 62 |
| 2020 | 37 |
| 2021 | 58 |
| 2022 | 33 |
| 2023 | 53 |
| 2024 | 81 |