| Year | Count |
|---|---|
| 1965 | 5 |
| 1966 | 21 |
| 1967 | 14 |
| 1968 | 30 |
| 1969 | 46 |
| 1970 | 84 |
| 1971 | 97 |
| 1972 | 113 |
| 1973 | 113 |
| 1974 | 113 |
| 1975 | 84 |
| 1976 | 74 |
| 1977 | 152 |
| 1978 | 136 |
| 1979 | 182 |
| 1980 | 238 |
| 1981 | 98 |
| 1982 | 104 |
| 1983 | 77 |
| 1984 | 78 |
| 1985 | 74 |
| 1986 | 55 |
| 1987 | 49 |
| 1988 | 57 |
| 1989 | 62 |
| 1990 | 62 |
| 1991 | 45 |
| 1992 | 33 |
| 1993 | 25 |
| 1994 | 27 |
| 1995 | 27 |
| 1996 | 16 |
| 1997 | 20 |
| 1998 | 16 |
| 1999 | 15 |
| 2000 | 10 |
| 2001 | 8 |
| 2003 | 7 |
| 2004 | 7 |
| 2006 | 6 |