Year US Dollars 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 772738000 1982 1313091000 1983 1738593000 1984 2583927000 1985 3851537000 1986 5866002000 1987 8265581000 1988 8943894000 1989 10137085000 1990 10889630000 1991 11741677000 1992 11838555000 1993 12177639000 1994 9828535000 1995 10378825000 1996 10368413000 1997 11099447000 1998 11404630000 1999 11794855000 2000 12008619000 2001 11274812000 2002 12313482000 2003 14259736000 2004 16620264000 2005 18507345000 2006 28007277000 2007 43822452000 2008 53065077000 2009 55670272000 2010 50634696000 2011 47642116000 2012 51299197000 2013 51473305000 2014 48083185000 2015 40115311000 2016 39656828000