Year	US Dollars
1962	2310
1963	2490
1964	2740
1965	2960
1966	3190
1967	3460
1968	3770
1969	4100
1970	4500
1971	4890
1972	5670
1973	7050
1974	8580
1975	10160
1976	10720
1977	11290
1978	12460
1979	14790
1980	17300
1981	17530
1982	15760
1983	13550
1984	13020
1985	13080
1986	15330
1987	19360
1988	24190
1989	26090
1990	27760
1991	29110
1992	31340
1993	28200
1994	27690
1995	28070
1996	30390
1997	31380
1998	31120
1999	30910
2000	31220
2001	29390
2002	28740
2003	32480
2004	39450
2005	45420
2006	48840
2007	52010
2008	55380
2009	51920
2010	53900
2011	55660
2012	58240
2013	60910
2014	60980
2015	57880
2016	54530
2017	52590