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	9731000
1993	385190000
1994	580286000
1995	633564000
1996	699361000
1997	1065027000
1998	1242772000
1999	1381613000
2000	1141071000
2001	1162076000
2002	1252992000
2003	1269664000
2004	1163509000
2005	1121433000
2006	1068155000
2007	1344269000
2008	2492573000
2009	2666449000
2010	3561643000
2011	3923584000
2012	4620535000
2013	4868394000
2014	5177945000
2015	5001714000
2016	4876658000