| Year | Count |
|---|---|
| 1966 | 8 |
| 1967 | 5 |
| 1969 | 12 |
| 1970 | 11 |
| 1972 | 33 |
| 1973 | 31 |
| 1974 | 12 |
| 1975 | 12 |
| 1976 | 26 |
| 1977 | 111 |
| 1978 | 101 |
| 1979 | 89 |
| 1980 | 70 |
| 1981 | 39 |
| 1982 | 75 |
| 1983 | 67 |
| 1984 | 60 |
| 1985 | 73 |
| 1986 | 111 |
| 1987 | 105 |
| 1988 | 98 |
| 1989 | 53 |
| 1990 | 69 |
| 1991 | 89 |
| 1992 | 123 |
| 1993 | 341 |
| 1994 | 133 |
| 1995 | 105 |
| 1996 | 95 |
| 1997 | 37 |
| 1998 | 15 |
| 1999 | 86 |
| 2000 | 10 |
| 2001 | 24 |
| 2002 | 5 |
| 2003 | 12 |