| Year | Count |
|---|---|
| 1967 | 10 |
| 1969 | 145 |
| 1970 | 122 |
| 1971 | 150 |
| 1972 | 47 |
| 1973 | 39 |
| 1974 | 108 |
| 1975 | 121 |
| 1976 | 80 |
| 1977 | 132 |
| 1978 | 83 |
| 1979 | 117 |
| 1980 | 93 |
| 1981 | 40 |
| 1982 | 37 |
| 1983 | 40 |
| 1984 | 25 |
| 1985 | 22 |
| 1986 | 37 |
| 1987 | 49 |
| 1988 | 14 |
| 1989 | 42 |
| 1990 | 60 |
| 1991 | 107 |
| 1992 | 94 |
| 1993 | 50 |
| 1994 | 40 |
| 1995 | 20 |
| 1996 | 36 |
| 1997 | 7 |
| 1998 | 22 |
| 1999 | 21 |
| 2000 | 25 |
| 2001 | 7 |
| 2002 | 10 |
| 2003 | 17 |
| 2004 | 7 |
| 2005 | 19 |
| 2006 | 26 |
| 2007 | 25 |
| 2008 | 13 |
| 2009 | 12 |
| 2010 | 10 |
| 2011 | 6 |
| 2012 | 5 |
| 2015 | 15 |