| Year | Count |
|---|---|
| 1968 | 26 |
| 1969 | 16 |
| 1970 | 22 |
| 1971 | 44 |
| 1972 | 43 |
| 1973 | 47 |
| 1974 | 30 |
| 1975 | 42 |
| 1976 | 63 |
| 1977 | 70 |
| 1978 | 85 |
| 1979 | 54 |
| 1980 | 25 |
| 1981 | 61 |
| 1982 | 32 |
| 1983 | 82 |
| 1984 | 86 |
| 1985 | 124 |
| 1986 | 85 |
| 1987 | 207 |
| 1988 | 130 |
| 1989 | 116 |
| 1990 | 66 |
| 1991 | 82 |
| 1992 | 53 |
| 1993 | 17 |
| 1994 | 62 |
| 1995 | 32 |
| 1996 | 26 |
| 2000 | 5 |