Year	US Dollars
1961	0.00255
1963	2.59937
1964	1.06024
1965	0.83649
1966	0.08717
1967	0.08026
1968	0.42977
1969	0.12886
1970	0.1134
1971	0.12119
1972	0.15001
1973	0.14879
1974	0.26764
1975	0.66097
1976	0.99708
1977	1.03672
1978	1.40777
1979	1.87655
1980	22.78605
1981	23.26909
1982	27.3429
1983	25.59103
1984	35.33936
1985	27.0755
1986	24.81787
1987	31.38565
1988	28.23361
1989	26.49816
1990	33.04959
1991	37.45297
1992	74.25456
1993	46.25417
1994	51.69914
1995	44.70604
1996	33.25768
1997	29.62754
1998	22.63004
1999	20.87918
2000	14.84113
2001	13.45062
2002	16.61543
2003	15.47886
2004	15.40184
2005	30.50696
2006	22.5652
2007	38.34845
2008	48.82335
2009	58.08841
2010	55.49398
2011	55.47305
2012	75.50434
2013	61.04863
2014	54.892
2015	55.69011
2016	45.26835
2017	49.20582
2018	52.78702
2019	54.97308
2020	62.83478
2021	60.92403