| Year | Count |
|---|---|
| 1968 | 15 |
| 1969 | 17 |
| 1970 | 28 |
| 1971 | 44 |
| 1972 | 58 |
| 1973 | 86 |
| 1974 | 117 |
| 1975 | 216 |
| 1976 | 175 |
| 1977 | 372 |
| 1978 | 270 |
| 1979 | 230 |
| 1980 | 192 |
| 1981 | 112 |
| 1982 | 107 |
| 1983 | 69 |
| 1984 | 94 |
| 1985 | 72 |
| 1986 | 69 |
| 1987 | 58 |
| 1988 | 74 |
| 1989 | 51 |
| 1990 | 45 |
| 1991 | 42 |
| 1992 | 28 |
| 1993 | 25 |
| 1994 | 15 |
| 1995 | 18 |
| 1996 | 12 |
| 1997 | 15 |
| 1998 | 10 |
| 1999 | 8 |
| 2000 | 9 |
| 2002 | 6 |
| 2003 | 6 |