| Year | Count |
|---|---|
| 1969 | 18 |
| 1970 | 48 |
| 1971 | 154 |
| 1972 | 231 |
| 1973 | 152 |
| 1974 | 201 |
| 1975 | 163 |
| 1976 | 125 |
| 1977 | 104 |
| 1978 | 112 |
| 1979 | 98 |
| 1980 | 120 |
| 1981 | 96 |
| 1982 | 77 |
| 1983 | 1,007 |
| 1984 | 1,470 |
| 1985 | 1,015 |
| 1986 | 709 |
| 1987 | 497 |
| 1988 | 423 |
| 1989 | 296 |
| 1990 | 312 |
| 1991 | 236 |
| 1992 | 174 |
| 1993 | 101 |
| 1994 | 115 |
| 1995 | 139 |
| 1996 | 204 |
| 1997 | 149 |
| 1998 | 145 |
| 1999 | 70 |
| 2000 | 71 |
| 2001 | 73 |
| 2002 | 170 |
| 2003 | 602 |
| 2004 | 712 |
| 2005 | 474 |
| 2006 | 372 |
| 2007 | 286 |
| 2008 | 247 |
| 2009 | 134 |
| 2010 | 82 |
| 2011 | 45 |
| 2012 | 21 |
| 2015 | 7 |