| Year | Count |
|---|---|
| 1956 | 5 |
| 1961 | 5 |
| 1963 | 5 |
| 1965 | 22 |
| 1967 | 28 |
| 1968 | 10 |
| 1969 | 15 |
| 1971 | 36 |
| 1973 | 8 |
| 1974 | 5 |
| 1977 | 42 |
| 1979 | 22 |
| 1980 | 35 |
| 1981 | 32 |
| 1982 | 10 |
| 1983 | 32 |
| 1984 | 37 |
| 1985 | 15 |
| 1986 | 25 |
| 1987 | 18 |
| 1988 | 19 |
| 1989 | 44 |
| 1990 | 20 |
| 1991 | 25 |
| 1992 | 33 |
| 1993 | 25 |
| 1994 | 41 |
| 1995 | 28 |
| 1996 | 44 |
| 1997 | 39 |
| 1998 | 78 |
| 1999 | 48 |
| 2000 | 7 |
| 2001 | 39 |
| 2002 | 48 |
| 2003 | 27 |
| 2004 | 55 |
| 2005 | 6 |
| 2006 | 52 |
| 2007 | 37 |
| 2008 | 34 |
| 2009 | 16 |
| 2010 | 25 |
| 2011 | 18 |
| 2012 | 10 |
| 2016 | 5 |