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	772738000
1982	1313091000
1983	1738593000
1984	2583927000
1985	3851537000
1986	5866002000
1987	8265581000
1988	8943894000
1989	10137085000
1990	10889630000
1991	11741677000
1992	11838555000
1993	12177639000
1994	9828535000
1995	10378825000
1996	10368413000
1997	11099447000
1998	11404630000
1999	11794855000
2000	12008619000
2001	11274812000
2002	12313482000
2003	14259736000
2004	16620264000
2005	18507345000
2006	28007277000
2007	43822452000
2008	53065077000
2009	55670272000
2010	50634696000
2011	47642116000
2012	51299197000
2013	51473305000
2014	48083185000
2015	40115311000
2016	39656828000