Year	US Dollars
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	1318276000
1985	2811175000
1986	3433372000
1987	4060842000
1988	4096323000
1989	4302431000
1990	4581082000
1991	4652994000
1992	5063943000
1993	5144681000
1994	5570271000
1995	5640031000
1996	5671487000
1997	5670155000
1998	6555480000
1999	5573511000
2000	5613499000
2001	3412083000
2002	3635896000
2003	3929257000
2004	4522716000
2005	4392397000
2006	2792102000
2007	3047735000
2008	3489361000
2009	4138419000
2010	4130755000
2011	4648510000
2012	5489817000
2013	7895389000
2014	8677914000
2015	9996132000
2016	10293919000