| Year | Count |
|---|---|
| 1963 | 5 |
| 1968 | 6 |
| 1969 | 6 |
| 1971 | 21 |
| 1972 | 18 |
| 1973 | 46 |
| 1974 | 43 |
| 1975 | 63 |
| 1976 | 50 |
| 1977 | 41 |
| 1978 | 76 |
| 1979 | 54 |
| 1980 | 32 |
| 1981 | 38 |
| 1982 | 31 |
| 1983 | 35 |
| 1984 | 24 |
| 1985 | 48 |
| 1986 | 21 |
| 1987 | 40 |
| 1988 | 22 |
| 1989 | 28 |
| 1990 | 47 |
| 1991 | 55 |
| 1992 | 69 |
| 1993 | 95 |
| 1994 | 73 |
| 1995 | 59 |
| 1996 | 126 |
| 1997 | 120 |
| 1998 | 93 |
| 1999 | 90 |
| 2000 | 61 |
| 2001 | 25 |
| 2002 | 28 |
| 2003 | 25 |
| 2004 | 47 |
| 2005 | 43 |
| 2006 | 43 |
| 2007 | 36 |
| 2008 | 33 |
| 2009 | 32 |
| 2010 | 5 |
| 2012 | 19 |
| 2013 | 7 |
| 2014 | 5 |
| 2015 | 30 |
| 2017 | 30 |
| 2019 | 38 |
| 2021 | 20 |