Year	US Dollars
1960	0.20467
1961	0.09365
1962	0.29137
1963	0.66703
1964	1.61047
1965	1.29617
1966	0.47815
1967	0.46109
1968	0.25011
1969	0.45269
1970	0.8215
1971	1.61104
1972	2.16135
1973	1.22331
1974	0.37623
1975	9.49678
1976	1.69176
1977	6.59022
1978	5.76612
1979	2.1838
1980	0.9104
1981	18.67954
1982	0.25021
1983	0.46096
1984	-0.12876
1985	1.26318
1986	1.75128
1987	5.20303
1988	0.38264
1989	0.62319
1990	3.57281
1991	30.95754
1992	7.51128
1993	8.74283
1994	12.51971
1995	15.88487
1996	16.16224
1997	9.9383
1998	5.10812
1999	3.22366
2000	4.13458
2001	4.82583
2002	4.31836
2003	84.51235
2004	166.93559
2005	768.57496
2006	307.52927
2007	321.14637
2008	338.29836
2009	92.15313
2010	69.6734
2011	59.13541
2012	38.41433
2013	43.44594
2014	37.26261
2015	39.27505
2016	59.122
2017	73.38275
2018	56.67826
2019	50.30782
2020	55.44213
2021	41.56285