| Year | Count |
|---|---|
| 1966 | 6 |
| 1968 | 55 |
| 1969 | 63 |
| 1970 | 81 |
| 1971 | 116 |
| 1972 | 185 |
| 1973 | 167 |
| 1974 | 154 |
| 1975 | 176 |
| 1976 | 209 |
| 1977 | 238 |
| 1978 | 257 |
| 1979 | 273 |
| 1980 | 265 |
| 1981 | 234 |
| 1982 | 251 |
| 1983 | 283 |
| 1984 | 314 |
| 1985 | 392 |
| 1986 | 373 |
| 1987 | 452 |
| 1988 | 444 |
| 1989 | 483 |
| 1990 | 539 |
| 1991 | 526 |
| 1992 | 450 |
| 1993 | 454 |
| 1994 | 401 |
| 1995 | 314 |
| 1996 | 411 |
| 1997 | 235 |
| 1998 | 168 |
| 1999 | 110 |
| 2000 | 81 |
| 2001 | 34 |
| 2002 | 63 |
| 2003 | 58 |
| 2004 | 34 |
| 2005 | 44 |
| 2006 | 28 |
| 2007 | 17 |
| 2008 | 7 |
| 2009 | 17 |
| 2016 | 7 |