Year	US Dollars
1960	19.91182
1961	30.07775
1962	57.38762
1963	41.06735
1964	15.23012
1965	20.31706
1966	23.87518
1967	52.41852
1968	48.07315
1969	57.89496
1970	49.21219
1971	41.18904
1972	32.06615
1973	36.80788
1974	48.35951
1975	66.58971
1976	87.13503
1977	69.97936
1978	131.14234
1979	146.0976
1980	99.90836
1981	76.02646
1982	78.93234
1983	96.50568
1984	87.02675
1985	134.18097
1986	143.90726
1987	137.326
1988	143.06389
1989	159.60156
1990	166.056
1991	116.75301
1992	137.46788
1993	160.21465
1994	162.13409
1995	92.50526
1996	100.21922
1997	63.42203
1998	64.56002
1999	203.66687
2000	67.17802
2001	90.64893
2002	90.94212
2003	48.03067
2004	24.62077
2005	41.80116
2006	26.77251
2007	71.60812
2008	76.45475
2009	83.52139
2010	75.13055
2011	63.69523
2012	77.76086
2013	148.74321
2014	106.60309
2015	78.55593
2016	95.17768
2017	91.27473
2018	88.54492
2019	91.16026
2020	175.47814
2021	193.13504