| Year | Count |
|---|---|
| 1959 | 8 |
| 1961 | 6 |
| 1962 | 5 |
| 1963 | 6 |
| 1964 | 11 |
| 1965 | 17 |
| 1966 | 15 |
| 1967 | 11 |
| 1968 | 21 |
| 1969 | 26 |
| 1970 | 21 |
| 1971 | 24 |
| 1972 | 16 |
| 1973 | 26 |
| 1974 | 30 |
| 1975 | 42 |
| 1976 | 54 |
| 1977 | 52 |
| 1978 | 54 |
| 1979 | 46 |
| 1980 | 80 |
| 1981 | 48 |
| 1982 | 52 |
| 1983 | 58 |
| 1984 | 70 |
| 1985 | 64 |
| 1986 | 74 |
| 1987 | 54 |
| 1988 | 44 |
| 1989 | 46 |
| 1990 | 64 |
| 1991 | 46 |
| 1992 | 29 |
| 1993 | 25 |
| 1994 | 72 |
| 1995 | 57 |
| 1996 | 60 |
| 1997 | 72 |
| 1998 | 93 |
| 1999 | 48 |
| 2000 | 69 |
| 2001 | 54 |
| 2002 | 18 |
| 2003 | 34 |
| 2004 | 24 |
| 2005 | 36 |
| 2006 | 29 |
| 2007 | 24 |
| 2008 | 27 |
| 2009 | 18 |
| 2010 | 16 |
| 2011 | 16 |
| 2012 | 8 |
| 2013 | 6 |
| 2014 | 7 |