Year Annual Number 1970 0 1971 0 1972 0 1973 2516 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 30020 1981 0 1982 0 1983 0 1984 0 1985 307 1986 0 1987 0 1988 810000 1989 0 1990 0 1991 0 1992 0 1993 0 1994 4 1995 0 1996 800 1997 0 1998 0 1999 0 2000 0 2001 201 2002 1504 2003 0 2004 350100 2005 10400 2006 0 2007 33190 2008 4013