Year	US Dollars
1970	197359000
1971	1175689000
1972	1395651000
1973	1743027000
1974	2012128000
1975	2341882000
1976	2702044000
1977	3470568000
1978	4369041000
1979	4204048000
1980	5242014000
1981	5759619000
1982	6133769000
1983	6801892000
1984	7164251000
1985	9095915000
1986	4897648000
1987	5503393000
1988	6008405000
1989	5848907000
1990	6430712000
1991	6556401000
1992	6666322000
1993	6766166000
1994	7225292000
1995	7368197000
1996	7341380000
1997	7103349000
1998	7503609000
1999	7905463000
2000	7186028000
2001	6509288000
2002	7144025000
2003	7306170000
2004	8626963000
2005	8400040000
2006	4096161000
2007	5029477000
2008	6009852000
2009	7685361000
2010	8893151000
2011	10012876000
2012	11588075000
2013	13140981000
2014	14352454000
2015	15504686000
2016	16474516000