Year US Dollars 1970 1493947000 1971 1998462000 1972 2613789000 1973 2881231000 1974 2722901000 1975 2290473000 1976 4998743000 1977 10790569000 1978 16630900000 1979 24101914000 1980 29382195000 1981 32151264000 1982 32181845000 1983 38321052000 1984 36900073000 1985 35344222000 1986 34349097000 1987 34576905000 1988 34742786000 1989 32380476000 1990 33172571000 1991 34123003000 1992 37849462000 1993 37540190000 1994 36943074000 1995 35744354000 1996 34763666000 1997 39947610000 1998 44179410000 1999 43484308000 2000 42753311000 2001 39552750000 2002 37132966000 2003 38105848000 2004 39193252000 2005 45357224000 2006 45167276000 2007 58712126000 2008 66930078000 2009 84578254000 2010 101765867000 2011 118171694000 2012 130629842000 2013 132345779000 2014 135747695000 2015 124386152000 2016 113023864000