| Year | Count |
|---|---|
| 1964 | 16 |
| 1966 | 45 |
| 1967 | 29 |
| 1968 | 23 |
| 1969 | 40 |
| 1970 | 83 |
| 1971 | 61 |
| 1972 | 105 |
| 1973 | 91 |
| 1974 | 106 |
| 1975 | 145 |
| 1976 | 143 |
| 1977 | 192 |
| 1978 | 132 |
| 1979 | 157 |
| 1980 | 108 |
| 1981 | 85 |
| 1982 | 118 |
| 1983 | 55 |
| 1984 | 109 |
| 1985 | 260 |
| 1986 | 265 |
| 1987 | 271 |
| 1988 | 290 |
| 1989 | 238 |
| 1990 | 253 |
| 1991 | 234 |
| 1992 | 202 |
| 1993 | 168 |
| 1994 | 111 |
| 1995 | 63 |
| 1996 | 78 |
| 1997 | 38 |
| 1998 | 14 |
| 1999 | 11 |
| 2000 | 7 |
| 2001 | 17 |
| 2002 | 15 |
| 2003 | 5 |
| 2004 | 16 |
| 2007 | 6 |