Year	US Dollars
1960	0.78323
1961	8.07924
1962	6.12552
1963	8.08223
1964	2.91968
1965	2.90837
1966	5.69709
1967	6.60784
1968	12.07395
1969	6.64693
1970	7.27603
1971	11.01009
1972	12.3936
1973	15.86459
1974	28.43827
1975	31.86099
1976	18.7864
1977	24.26797
1978	46.89882
1979	33.73029
1980	34.25328
1981	59.44136
1982	48.06951
1983	40.07224
1984	33.00663
1985	26.10413
1986	52.53024
1987	60.41993
1988	54.93468
1989	57.39779
1990	83.38882
1991	62.90025
1992	42.1323
1993	24.36726
1994	13.33518
1995	21.2213
1996	17.92775
1997	36.62857
1998	34.82357
1999	35.5834
2000	17.48292
2001	17.78837
2002	19.79876
2003	-11.96667
2004	26.86316
2005	28.00724
2006	15.50248
2007	55.83117
2008	87.35485
2009	125.08127
2010	99.64011
2011	148.26686
2012	140.682
2013	115.76526
2014	35.35499
2015	62.09621
2016	33.50354
2017	11.56625
2018	54.69442
2019	17.55155
2020	264.60212
2021	231.5345