Year US Dollars 1970 2746452000 1971 3287189000 1972 3554567000 1973 4204213000 1974 4632821000 1975 5058838000 1976 6001278000 1977 11452267000 1978 14854965000 1979 15928439000 1980 19131091000 1981 19235547000 1982 19715952000 1983 20324057000 1984 21607733000 1985 26012629000 1986 32933707000 1987 40943571000 1988 40992856000 1989 41577123000 1990 49424156000 1991 50873480000 1992 56553854000 1993 68604754000 1994 66249182000 1995 73781102000 1996 80624827000 1997 84719907000 1998 96953866000 1999 101784253000 2000 116799282000 2001 112946286000 2002 129501121000 2003 144076069000 2004 159621567000 2005 173601952000 2006 211039511000 2007 260028248000 2008 290571653000 2009 278829980000 2010 300869524000 2011 305569781000 2012 338827811000 2013 390353934000 2014 402558688000 2015 396664940000 2016 405656066000