| Year | Count |
|---|---|
| 1965 | 11 |
| 1967 | 6 |
| 1968 | 6 |
| 1969 | 9 |
| 1970 | 7 |
| 1971 | 14 |
| 1972 | 50 |
| 1973 | 72 |
| 1974 | 61 |
| 1975 | 84 |
| 1976 | 72 |
| 1977 | 182 |
| 1978 | 202 |
| 1979 | 198 |
| 1980 | 210 |
| 1981 | 117 |
| 1982 | 125 |
| 1983 | 104 |
| 1984 | 101 |
| 1985 | 64 |
| 1986 | 81 |
| 1987 | 69 |
| 1988 | 79 |
| 1989 | 72 |
| 1990 | 99 |
| 1991 | 80 |
| 1992 | 88 |
| 1993 | 97 |
| 1994 | 107 |
| 1995 | 115 |
| 1996 | 72 |
| 1997 | 62 |
| 1998 | 41 |
| 1999 | 35 |
| 2000 | 29 |
| 2001 | 25 |
| 2002 | 18 |
| 2003 | 8 |
| 2004 | 10 |
| 2005 | 12 |
| 2006 | 8 |
| 2007 | 6 |
| 2009 | 9 |
| 2011 | 5 |
| 2012 | 5 |
| 2017 | 15 |