Year Annual Number 1970 0 1971 0 1972 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 1853 1980 0 1981 11100 1982 0 1983 0 1984 1000 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 37 1992 0 1993 0 1994 0 1995 0 1996 45100 1997 20270 1998 467 1999 0 2000 0 2001 23800 2002 0 2003 8204 2004 3310 2005 615 2006 8186 2007 22260 2008 2250