Year	US Dollars
1970	5984158000
1971	7726268000
1972	11863652000
1973	15066010000
1974	22464944000
1975	27781562000
1976	33801314000
1977	42500190000
1978	55032105000
1979	61795267000
1980	71983914000
1981	81914151000
1982	94428715000
1983	99022192000
1984	104364920000
1985	104173243000
1986	109645175000
1987	120476588000
1988	118039403000
1989	114930117000
1990	120311880000
1991	121336721000
1992	129535946000
1993	144599584000
1994	152903119000
1995	160964216000
1996	181793533000
1997	198980295000
1998	241998416000
1999	245114974000
2000	242511682000
2001	229959721000
2002	231944172000
2003	235907976000
2004	220693598000
2005	188364548000
2006	194303020000
2007	238444455000
2008	262957242000
2009	281651132000
2010	352364412000
2011	404046105000
2012	440514543000
2013	483765356000
2014	556920799000
2015	543397349000
2016	543257252000