Year US Dollars 1970 3299810000 1971 3409739000 1972 3585308000 1973 4023443000 1974 5380537000 1975 6263822000 1976 7725085000 1977 9323180000 1978 9864919000 1979 9416573000 1980 9534079000 1981 8742796000 1982 10871147000 1983 11510205000 1984 12325640000 1985 13049985000 1986 15046005000 1987 17636120000 1988 18380471000 1989 18770834000 1990 20297682000 1991 20804190000 1992 20421071000 1993 23650217000 1994 26596517000 1995 30911666000 1996 29032994000 1997 29724009000 1998 30581704000 1999 29361511000 2000 28834465000 2001 27722609000 2002 28425471000 2003 30166301000 2004 31742551000 2005 29513669000 2006 29295980000 2007 32239017000 2008 34719590000 2009 37389856000 2010 42153894000 2011 45012108000 2012 54558515000 2013 56802792000 2014 61269605000 2015 65940554000 2016 69503047000