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	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	5527000
1993	292084000
1994	446759000
1995	609470000
1996	1136991000
1997	1340945000
1998	1505066000
1999	1852208000
2000	1937816000
2001	1823859000
2002	1957507000
2003	2148375000
2004	2560867000
2005	2256599000
2006	2596156000
2007	2878750000
2008	3628105000
2009	4118815000
2010	4114487000
2011	5485932000
2012	6025991000
2013	6803753000
2014	7264357000
2015	7510751000
2016	7876314000