Year	US Dollars
1960	0.00991
1961	1.05582
1962	1.75336
1963	1.73193
1964	5.05588
1965	5.47606
1966	5.59337
1967	5.72846
1968	6.15861
1969	6.60612
1970	6.09425
1971	8.12551
1972	8.05094
1973	11.57196
1974	19.61726
1975	16.33893
1976	14.62389
1977	19.25186
1978	28.55004
1979	19.24622
1980	7.93743
1981	13.50804
1982	13.87679
1983	17.99277
1984	22.64175
1985	36.04364
1986	31.3218
1987	38.06746
1988	47.54481
1989	44.18742
1990	53.29952
1991	43.41136
1992	37.55399
1993	34.65575
1994	32.19931
1995	34.11597
1996	41.0789
1997	30.59507
1998	22.62776
1999	23.54455
2000	15.90118
2001	22.0874
2002	25.93804
2003	27.40104
2004	34.54308
2005	38.62464
2006	28.04754
2007	34.31775
2008	39.80749
2009	48.56679
2010	41.20818
2011	37.15457
2012	37.25076
2013	34.75434
2014	28.61403
2015	42.88955
2016	42.79297
2017	43.01902
2018	56.09384
2019	39.80438
2020	62.30271
2021	42.03498