| Year | Count |
|---|---|
| 1972 | 5 |
| 1973 | 7 |
| 1974 | 10 |
| 1975 | 11 |
| 1976 | 12 |
| 1977 | 24 |
| 1978 | 36 |
| 1979 | 28 |
| 1980 | 8 |
| 1981 | 14 |
| 1982 | 13 |
| 1985 | 13 |
| 1986 | 14 |
| 1987 | 20 |
| 1988 | 28 |
| 1989 | 55 |
| 1990 | 51 |
| 1991 | 59 |
| 1992 | 110 |
| 1993 | 140 |
| 1994 | 146 |
| 1995 | 154 |
| 1996 | 215 |
| 1997 | 250 |
| 1998 | 233 |
| 1999 | 165 |
| 2000 | 154 |
| 2001 | 170 |
| 2002 | 112 |
| 2003 | 129 |
| 2004 | 154 |
| 2005 | 174 |
| 2006 | 130 |
| 2007 | 120 |
| 2008 | 98 |
| 2009 | 62 |
| 2010 | 102 |
| 2011 | 79 |
| 2012 | 88 |
| 2013 | 57 |
| 2014 | 84 |
| 2015 | 94 |
| 2016 | 69 |
| 2017 | 73 |
| 2018 | 101 |
| 2019 | 40 |
| 2020 | 106 |
| 2021 | 88 |
| 2022 | 34 |
| 2023 | 69 |
| 2024 | 80 |