Year	US Dollars
1962	1450
1963	1530
1964	1670
1965	1800
1966	1950
1967	2100
1968	2270
1969	2510
1970	2790
1971	3090
1972	3660
1973	4710
1974	6020
1975	6940
1976	7620
1977	8260
1978	9610
1979	11790
1980	14050
1981	13260
1982	11240
1983	9470
1984	8910
1985	8870
1986	10210
1987	13160
1988	17090
1989	18120
1990	19400
1991	20680
1992	23280
1993	23520
1994	25210
1995	27200
1996	28760
1997	28650
1998	26720
1999	26180
2000	26040
2001	24530
2002	24130
2003	27120
2004	32970
2005	37850
2006	40030
2007	42780
2008	46720
2009	46270
2010	47920
2011	47080
2012	47190
2013	47400
2014	46970
2015	44230
2016	42640
2017	41790