Year	US Dollars
1960	13.78897
1961	14.69513
1962	16.47012
1963	20.50562
1964	19.71425
1965	27.92171
1966	34.14484
1967	37.57821
1968	40.7994
1969	44.24017
1970	47.56036
1971	39.88402
1972	69.05804
1973	62.25377
1974	62.55367
1975	112.70994
1976	94.71683
1977	77.98722
1978	119.61887
1979	107.7569
1980	175.7194
1981	114.87551
1982	104.85514
1983	98.82408
1984	68.64168
1985	68.76944
1986	96.5005
1987	177.6322
1988	170.90964
1989	145.09155
1990	128.35818
1991	110.31526
1992	128.92683
1993	150.89555
1994	128.64021
1995	127.48242
1996	110.7315
1997	105.25123
1998	70.14664
1999	95.58022
2000	159.03139
2001	134.37936
2002	58.07969
2003	134.29716
2004	257.65973
2005	407.86674
2006	404.71799
2007	469.99815
2008	434.41777
2009	389.85815
2010	615.93949
2011	592.13937
2012	537.37212
2013	497.67755
2014	335.66856
2015	310.17203
2016	279.41322
2017	290.24259
2018	296.64057
2019	331.69233
2020	309.98667
2021	372.55014