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