Year	US Dollars
1962	1630
1963	1680
1964	1870
1965	1920
1966	2020
1967	2070
1968	2240
1969	2560
1970	3040
1971	3360
1972	4090
1973	5250
1974	6910
1975	7960
1976	8540
1977	9100
1978	10680
1979	12980
1980	15520
1981	15530
1982	14970
1983	13520
1984	13100
1985	13160
1986	15650
1987	20150
1988	26090
1989	28780
1990	31590
1991	35460
1992	39320
1993	40390
1994	41680
1995	46150
1996	48740
1997	50790
1998	47230
1999	46600
2000	46590
2001	45750
2002	42740
2003	46120
2004	62970
2005	74020
2006	71780
2007	86450
2008	88240
2009	71410
2010	78440
2011	76890
2012	75450
2013	75500
2014	75280
2015	73530
2016	71590
2017	70260