Year US Dollars 1970 603180000 1971 676472000 1972 753134000 1973 881777000 1974 1008319000 1975 1115792000 1976 1290715000 1977 2248217000 1978 2954539000 1979 3410541000 1980 3533401000 1981 3611173000 1982 3777324000 1983 4063243000 1984 4097301000 1985 4886590000 1986 5944695000 1987 6817910000 1988 6800241000 1989 6974801000 1990 7689860000 1991 8251262000 1992 8542690000 1993 8693830000 1994 9614054000 1995 10819486000 1996 11379075000 1997 11229239000 1998 10845589000 1999 11912140000 2000 11355173000 2001 12916183000 2002 15490954000 2003 18109298000 2004 19558062000 2005 17922223000 2006 18665139000 2007 20504800000 2008 21381015000 2009 22721908000 2010 22471865000 2011 22641825000 2012 25261471000 2013 25661397000 2014 26371914000 2015 27130593000 2016 28110513000