| Year | Count |
|---|---|
| 1971 | 10 |
| 1972 | 29 |
| 1973 | 33 |
| 1974 | 46 |
| 1975 | 57 |
| 1976 | 100 |
| 1977 | 114 |
| 1978 | 57 |
| 1979 | 90 |
| 1980 | 19 |
| 1981 | 21 |
| 1982 | 21 |
| 1983 | 22 |
| 1984 | 25 |
| 1985 | 6 |
| 1986 | 15 |
| 1987 | 27 |
| 1988 | 18 |
| 1989 | 22 |
| 1990 | 51 |
| 1991 | 35 |
| 1992 | 125 |
| 1993 | 108 |
| 1994 | 144 |
| 1995 | 107 |
| 1996 | 42 |
| 1997 | 31 |
| 1998 | 111 |
| 1999 | 120 |
| 2000 | 307 |
| 2001 | 259 |
| 2002 | 142 |
| 2003 | 116 |
| 2004 | 116 |
| 2005 | 112 |
| 2006 | 110 |
| 2007 | 73 |
| 2008 | 51 |
| 2009 | 60 |
| 2010 | 8 |
| 2011 | 25 |
| 2013 | 16 |
| 2014 | 5 |
| 2017 | 22 |
| 2019 | 12 |
| 2021 | 5 |
| 2024 | 5 |