Year	US Dollars
1970	0
1971	0
1972	30147000
1973	108914000
1974	138780000
1975	210868000
1976	524566000
1977	755809000
1978	959936000
1979	3583369000
1980	9762280000
1981	10446728000
1982	10003165000
1983	9128470000
1984	7757570000
1985	7008018000
1986	6983318000
1987	6579983000
1988	2960341000
1989	1086836000
1990	1139859000
1991	2159379000
1992	3272088000
1993	4281772000
1994	5601781000
1995	6832097000
1996	8454021000
1997	9636706000
1998	10107804000
1999	9110876000
2000	11259184000
2001	12740487000
2002	16781889000
2003	22739464000
2004	29689399000
2005	38884066000
2006	53980690000
2007	84381085000
2008	99447359000
2009	113615501000
2010	115392635000
2011	119601150000
2012	120825677000
2013	123953892000
2014	111824203000
2015	96448286000
2016	95888350000