Year Annual Number 1970 0 1971 0 1972 0 1973 0 1974 103 1975 0 1976 0 1977 0 1978 2647 1979 27 1980 82 1981 0 1982 1100 1983 208 1984 29 1985 20 1986 0 1987 22650 1988 0 1989 0 1990 0 1991 0 1992 32 1993 18120 1994 1792 1995 548500 1996 0 1997 0 1998 0 1999 0 2000 7233 2001 11260 2002 0 2003 21270 2004 62220 2005 4431 2006 0 2007 55240 2008 841