Year	US Dollars
1970	31738000
1971	33286000
1972	35860000
1973	42350000
1974	47814000
1975	52179000
1976	64922000
1977	101516000
1978	190057000
1979	306193000
1980	420230000
1981	504757000
1982	550036000
1983	512033000
1984	510117000
1985	577757000
1986	634221000
1987	785231000
1988	824026000
1989	812914000
1990	932293000
1991	991773000
1992	943715000
1993	901104000
1994	1098539000
1995	1415083000
1996	1398985000
1997	1339676000
1998	1281159000
1999	1292871000
2000	966764000
2001	867308000
2002	931115000
2003	1003326000
2004	948588000
2005	805000000
2006	670171000
2007	714362000
2008	670775000
2009	2265007000
2010	2733923000
2011	9532558000
2012	10111237000
2013	13316656000
2014	15202110000
2015	14642562000
2016	17952076000