Year Annual Number 1970 0 1971 0 1972 3500000 1973 0 1974 0 1975 0 1976 0 1977 0 1978 17280 1979 0 1980 0 1981 0 1982 280 1983 0 1984 2230 1985 0 1986 1084 1987 0 1988 0 1989 0 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 1066000 1998 0 1999 0 2000 0 2001 0 2002 0 2003 15000 2004 0 2005 0 2006 0 2007 0 2008 0