Year	US Dollars
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	2183000
1978	10316000
1979	16719000
1980	23460000
1981	34421000
1982	37836000
1983	43793000
1984	54044000
1985	62646000
1986	78920000
1987	97673000
1988	109171000
1989	134446000
1990	150046000
1991	167713000
1992	189843000
1993	209812000
1994	222778000
1995	245656000
1996	235378000
1997	238210000
1998	258263000
1999	321784000
2000	304832000
2001	308356000
2002	333451000
2003	339962000
2004	361057000
2005	335608000
2006	351557000
2007	166185000
2008	131726000
2009	157003000
2010	181090000
2011	230970000
2012	201622000
2013	214377000
2014	212946000
2015	249357000
2016	247976000