Year	US Dollars
1970	2682000
1971	2610000
1972	4380000
1973	9456000
1974	13797000
1975	17392000
1976	22630000
1977	31254000
1978	41242000
1979	52517000
1980	59192000
1981	62601000
1982	65782000
1983	67687000
1984	73525000
1985	75128000
1986	74760000
1987	79617000
1988	74957000
1989	73538000
1990	91807000
1991	113649000
1992	117764000
1993	140499000
1994	154590000
1995	160046000
1996	153446000
1997	138790000
1998	143915000
1999	148000000
2000	139172000
2001	135465000
2002	148294000
2003	168610000
2004	176494000
2005	169098000
2006	165440000
2007	187695000
2008	207365000
2009	252886000
2010	325099000
2011	368309000
2012	422905000
2013	447234000
2014	450184000
2015	437424000
2016	417455000