Year	US Dollars
1970	813520000
1971	857446000
1972	943512000
1973	1030649000
1974	1196330000
1975	1681369000
1976	1893527000
1977	2336026000
1978	2578003000
1979	3039850000
1980	3252572000
1981	3609975000
1982	3662595000
1983	3745392000
1984	3751427000
1985	4487166000
1986	5633311000
1987	6480351000
1988	6694153000
1989	6553432000
1990	6904821000
1991	6958490000
1992	6700066000
1993	6477912000
1994	6808523000
1995	6957805000
1996	7060060000
1997	6659844000
1998	6870439000
1999	5953053000
2000	5811476000
2001	6189777000
2002	6674671000
2003	6874318000
2004	7540235000
2005	5460805000
2006	2375621000
2007	2857153000
2008	3079658000
2009	3774356000
2010	4384218000
2011	5099158000
2012	5857018000
2013	5884844000
2014	7524170000
2015	8742426000
2016	9547794000