| Year | Count |
|---|---|
| 1970 | 13 |
| 1971 | 7 |
| 1972 | 27 |
| 1973 | 35 |
| 1974 | 77 |
| 1975 | 73 |
| 1976 | 63 |
| 1977 | 76 |
| 1978 | 96 |
| 1979 | 53 |
| 1980 | 77 |
| 1981 | 56 |
| 1982 | 30 |
| 1983 | 58 |
| 1984 | 35 |
| 1985 | 21 |
| 1986 | 33 |
| 1987 | 53 |
| 1988 | 40 |
| 1989 | 44 |
| 1990 | 113 |
| 1991 | 98 |
| 1992 | 146 |
| 1993 | 146 |
| 1994 | 95 |
| 1995 | 118 |
| 1996 | 199 |
| 1997 | 136 |
| 1998 | 64 |
| 1999 | 61 |
| 2000 | 58 |
| 2001 | 69 |
| 2002 | 25 |
| 2003 | 33 |
| 2004 | 41 |
| 2005 | 19 |
| 2006 | 11 |
| 2007 | 13 |
| 2008 | 7 |
| 2009 | 5 |
| 2010 | 9 |
| 2011 | 21 |
| 2012 | 24 |
| 2013 | 18 |
| 2014 | 40 |
| 2015 | 39 |
| 2016 | 94 |
| 2017 | 59 |
| 2018 | 38 |
| 2019 | 68 |
| 2020 | 70 |
| 2021 | 42 |
| 2022 | 59 |
| 2023 | 55 |
| 2024 | 18 |