Year	US Dollars
1970	402121000
1971	432362000
1972	535905000
1973	573941000
1974	708699000
1975	993880000
1976	1214106000
1977	2485662000
1978	4088903000
1979	4637392000
1980	6108963000
1981	7772614000
1982	7807597000
1983	7692946000
1984	8400085000
1985	8792331000
1986	9418380000
1987	10553610000
1988	10808844000
1989	11376124000
1990	12162489000
1991	12520884000
1992	12262381000
1993	14119671000
1994	18104798000
1995	17001803000
1996	17448114000
1997	18355389000
1998	18544445000
1999	19159134000
2000	17112898000
2001	17744384000
2002	19515997000
2003	19906138000
2004	20562092000
2005	20357305000
2006	20319892000
2007	21043043000
2008	19050114000
2009	13350575000
2010	15045683000
2011	15898725000
2012	16400364000
2013	18618706000
2014	24158307000
2015	27257426000
2016	34083487000