Year	US Dollars
1961	12.66365
1966	9.55447
1967	2.72398
1969	0.0359
1975	28.41889
1976	78.07436
1977	84.23053
1978	112.48537
1979	103.44114
1980	194.93497
1981	151.38325
1982	157.48393
1983	169.77318
1984	180.64046
1985	189.21717
1986	302.31998
1987	242.20143
1988	233.24548
1989	231.69064
1990	288.7841
1991	273.66314
1992	304.96379
1993	293.4532
1994	297.94226
1995	281.32005
1996	276.62248
1997	257.77074
1998	294.78845
1999	304.63029
2000	206.5462
2001	167.52582
2002	195.46479
2003	302.71471
2004	295.48915
2005	330.48107
2006	278.84238
2007	328.98583
2008	434.77239
2009	381.60493
2010	627.34552
2011	476.51183
2012	460.11718
2013	454.05046
2014	423.73223
2015	277.54335
2016	206.37757
2017	217.73455
2018	147.5485
2019	263.31387
2020	270.69889
2021	255.33868