Year	US Dollars
1966	27.80703
1967	43.2416
1968	34.13474
1969	26.94892
1970	32.55609
1971	35.4123
1972	39.8537
1973	66.81126
1974	100.61865
1975	76.9901
1976	87.46235
1977	40.54979
1978	43.64515
1979	61.54852
1980	131.72803
1981	137.19503
1982	109.69506
1983	105.66159
1984	116.71917
1985	125.46253
1986	118.96868
1987	136.23525
1988	125.51768
1989	105.0326
1990	104.10119
1991	143.12297
1992	105.67562
1993	104.93872
1994	81.73558
1995	85.99305
1996	79.30599
1997	59.79807
1998	78.72718
1999	41.96086
2000	35.97524
2001	50.51658
2002	49.33396
2003	43.16559
2004	44.53208
2005	39.04279
2006	52.92248
2007	73.02654
2008	66.78635
2009	79.03588
2010	106.56623
2011	82.60318
2012	148.43263
2013	116.14358
2014	104.88209
2015	90.15141
2016	72.02854
2017	88.25414
2018	117.195
2019	92.95992
2020	163.7876
2021	185.48607