| Year | Count |
|---|---|
| 1971 | 23 |
| 1972 | 11 |
| 1973 | 10 |
| 1974 | 26 |
| 1975 | 32 |
| 1976 | 117 |
| 1977 | 87 |
| 1978 | 176 |
| 1979 | 200 |
| 1980 | 181 |
| 1981 | 159 |
| 1982 | 156 |
| 1983 | 168 |
| 1984 | 139 |
| 1985 | 167 |
| 1986 | 98 |
| 1987 | 90 |
| 1988 | 85 |
| 1989 | 62 |
| 1990 | 52 |
| 1991 | 31 |
| 1992 | 21 |
| 1993 | 18 |
| 1994 | 23 |
| 1995 | 10 |
| 1996 | 10 |
| 1998 | 10 |
| 1999 | 14 |
| 2000 | 8 |
| 2002 | 6 |
| 2003 | 5 |
| 2007 | 10 |