| Year | Count |
|---|---|
| 1969 | 5 |
| 1970 | 5 |
| 1971 | 6 |
| 1972 | 29 |
| 1973 | 22 |
| 1974 | 22 |
| 1975 | 34 |
| 1976 | 37 |
| 1977 | 52 |
| 1978 | 102 |
| 1979 | 103 |
| 1980 | 70 |
| 1981 | 38 |
| 1982 | 103 |
| 1983 | 74 |
| 1984 | 60 |
| 1985 | 61 |
| 1986 | 32 |
| 1987 | 65 |
| 1988 | 106 |
| 1989 | 90 |
| 1990 | 101 |
| 1991 | 66 |
| 1992 | 42 |
| 1993 | 38 |
| 1994 | 35 |
| 1995 | 6 |
| 1996 | 8 |
| 1997 | 5 |
| 1998 | 5 |
| 2002 | 10 |