| Year | Count |
|---|---|
| 1966 | 22 |
| 1967 | 30 |
| 1968 | 22 |
| 1969 | 41 |
| 1970 | 28 |
| 1971 | 26 |
| 1972 | 22 |
| 1973 | 24 |
| 1974 | 24 |
| 1975 | 20 |
| 1976 | 27 |
| 1977 | 60 |
| 1978 | 42 |
| 1979 | 40 |
| 1980 | 60 |
| 1981 | 33 |
| 1982 | 25 |
| 1983 | 25 |
| 1984 | 35 |
| 1985 | 33 |
| 1986 | 37 |
| 1987 | 30 |
| 1988 | 23 |
| 1989 | 23 |
| 1990 | 29 |
| 1991 | 23 |
| 1992 | 16 |
| 1993 | 13 |
| 1994 | 7 |
| 1995 | 13 |
| 1996 | 14 |
| 1997 | 10 |
| 1998 | 12 |
| 1999 | 14 |
| 2000 | 9 |
| 2001 | 6 |
| 2006 | 7 |
| 2008 | 5 |