Year	US Dollars
1970	232363000
1971	238494000
1972	218823000
1973	217480000
1974	217427000
1975	186855000
1976	143901000
1977	199463000
1978	446078000
1979	559236000
1980	785615000
1981	1259852000
1982	1871513000
1983	2191485000
1984	2179806000
1985	2413670000
1986	2621405000
1987	2884368000
1988	2695286000
1989	2819931000
1990	3278796000
1991	3473447000
1992	4124869000
1993	4249519000
1994	4485834000
1995	4989204000
1996	4984770000
1997	4881174000
1998	4598543000
1999	4337205000
2000	3842580000
2001	3654758000
2002	3978828000
2003	4603972000
2004	4953821000
2005	4445301000
2006	4909388000
2007	5709496000
2008	5712967000
2009	6002724000
2010	6607289000
2011	7313851000
2012	8659011000
2013	8199910000
2014	8039200000
2015	8738004000
2016	8897584000