Year US Dollars 1970 3406730000 1971 3795852000 1972 4072129000 1973 4566906000 1974 5121326000 1975 5752864000 1976 6802361000 1977 7564134000 1978 8329297000 1979 8918877000 1980 9931194000 1981 10580761000 1982 11703996000 1983 12026221000 1984 12227889000 1985 13464893000 1986 14954401000 1987 16797661000 1988 17065163000 1989 18348190000 1990 20663378000 1991 23363323000 1992 24917888000 1993 24546385000 1994 27382727000 1995 30228712000 1996 29834515000 1997 30078631000 1998 32283221000 1999 34142865000 2000 33021538000 2001 31914738000 2002 33806946000 2003 36464318000 2004 36331635000 2005 34017893000 2006 37174398000 2007 42006037000 2008 49523536000 2009 56339767000 2010 62801080000 2011 64468905000 2012 62066490000 2013 57881485000 2014 61146693000 2015 65757391000 2016 72697473000