Year	US Dollars
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	7288778000
1990	8591892000
1991	9000343000
1992	10059205000
1993	10571380000
1994	11292746000
1995	11502046000
1996	10545818000
1997	9948271000
1998	10784070000
1999	10673235000
2000	9763470000
2001	8776913000
2002	9109540000
2003	9099853000
2004	9786023000
2005	12223964000
2006	9890494000
2007	11931682000
2008	15501573000
2009	17014272000
2010	16949092000
2011	19298252000
2012	21106468000
2013	25003929000
2014	28902789000
2015	27991041000
2016	35364607000