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	511485000
1992	632621000
1993	786034000
1994	883115000
1995	458860000
1996	491993000
1997	516477000
1998	623593000
1999	773092000
2000	1122377000
2001	1154928000
2002	1181526000
2003	1552159000
2004	1606136000
2005	2101163000
2006	2465359000
2007	2897759000
2008	4238095000
2009	4587526000
2010	5372210000
2011	6330295000
2012	7176164000
2013	8821558000
2014	8488153000
2015	8350309000
2016	8437141000