Year	US Dollars
1970	2329426000
1971	3115341000
1972	3932626000
1973	4798033000
1974	5640712000
1975	6626720000
1976	8317652000
1977	10136188000
1978	12541324000
1979	15981335000
1980	18494668000
1981	20652769000
1982	19905764000
1983	20481895000
1984	19647970000
1985	22254001000
1986	21502882000
1987	22471937000
1988	21177809000
1989	19072883000
1990	17792821000
1991	16472059000
1992	16483024000
1993	12708822000
1994	11100631000
1995	10785299000
1996	9409824000
1997	10616367000
1998	10897971000
1999	10978473000
2000	11573165000
2001	12478684000
2002	11400901000
2003	14259748000
2004	14562777000
2005	16159381000
2006	19885771000
2007	26211640000
2008	30493343000
2009	33813839000
2010	32934661000
2011	31724198000
2012	34444376000
2013	36397427000
2014	33078634000
2015	31364245000
2016	29599394000