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	0
1993	276435000
1994	431046000
1995	402247000
1996	756163000
1997	1866476000
1998	2397437000
1999	2732208000
2000	2627004000
2001	2241509000
2002	2130947000
2003	1916766000
2004	1815781000
2005	1152800000
2006	991051000
2007	851749000
2008	738721000
2009	671475000
2010	529121000
2011	454309000
2012	503886000
2013	506854000
2014	411187000
2015	402877000
2016	508683000