Year	US Dollars
1960	2.53863
1961	2.35668
1962	3.54246
1963	2.10572
1964	2.21838
1965	2.4398
1966	3.45817
1967	3.78367
1968	4.39103
1969	4.67193
1970	5.57956
1971	6.2584
1972	7.27589
1973	9.11378
1974	10.60102
1975	20.01215
1976	16.94417
1977	19.8526
1978	25.24201
1979	29.01048
1980	29.36809
1981	28.16997
1982	26.57928
1983	25.38146
1984	26.87589
1985	28.18526
1986	31.55374
1987	35.47744
1988	35.21871
1989	31.59211
1990	39.33354
1991	47.9796
1992	45.56883
1993	44.77187
1994	105.71594
1995	122.15801
1996	69.28885
1997	29.96453
1998	44.23825
1999	46.58667
2000	39.63754
2001	37.0455
2002	42.94993
2003	39.21105
2004	55.86308
2005	63.44904
2006	65.3059
2007	81.90972
2008	95.63488
2009	93.01817
2010	100.21213
2011	119.43066
2012	81.05285
2013	97.85207
2014	91.04407
2015	93.54323
2016	96.42777
2017	100.67832
2018	89.34864
2019	91.02279
2020	123.57944
2021	97.65792