Year	US Dollars
1970	2196026000
1971	2419454000
1972	2671172000
1973	2761258000
1974	3305259000
1975	4170677000
1976	6039467000
1977	8183425000
1978	10772163000
1979	13281602000
1980	17417200000
1981	20785923000
1982	24412641000
1983	24211101000
1984	24356705000
1985	26637311000
1986	28204156000
1987	29784757000
1988	28932156000
1989	28652836000
1990	30579847000
1991	32493341000
1992	33219034000
1993	36142370000
1994	40256580000
1995	39378713000
1996	44001188000
1997	50705832000
1998	53608204000
1999	58480716000
2000	58455894000
2001	58399716000
2002	60064412000
2003	62762528000
2004	61148530000
2005	58692717000
2006	57597470000
2007	59175563000
2008	58269791000
2009	55984122000
2010	65358008000
2011	66114019000
2012	69371698000
2013	66202034000
2014	78558682000
2015	80622659000
2016	77319196000