| Year | Count |
|---|---|
| 1966 | 12 |
| 1967 | 37 |
| 1968 | 71 |
| 1969 | 69 |
| 1970 | 114 |
| 1971 | 98 |
| 1972 | 182 |
| 1973 | 119 |
| 1974 | 162 |
| 1975 | 209 |
| 1976 | 233 |
| 1977 | 290 |
| 1978 | 315 |
| 1979 | 362 |
| 1980 | 352 |
| 1981 | 317 |
| 1982 | 319 |
| 1983 | 406 |
| 1984 | 344 |
| 1985 | 375 |
| 1986 | 356 |
| 1987 | 296 |
| 1988 | 324 |
| 1989 | 329 |
| 1990 | 314 |
| 1991 | 303 |
| 1992 | 259 |
| 1993 | 229 |
| 1994 | 174 |
| 1995 | 168 |
| 1996 | 138 |
| 1997 | 144 |
| 1998 | 100 |
| 1999 | 89 |
| 2000 | 95 |
| 2001 | 51 |
| 2002 | 12 |
| 2004 | 52 |
| 2005 | 35 |
| 2006 | 33 |
| 2007 | 16 |
| 2008 | 19 |
| 2009 | 20 |
| 2010 | 17 |
| 2011 | 5 |
| 2012 | 10 |
| 2014 | 10 |
| 2015 | 12 |