Year	US Dollars
1960	2.59307
1961	3.43002
1962	2.66926
1963	3.22793
1964	4.58772
1965	4.85549
1966	3.93207
1967	3.45045
1968	6.1838
1969	4.59024
1970	5.00943
1971	4.09416
1972	5.52432
1973	4.58198
1974	6.21704
1975	11.64428
1976	8.95102
1977	9.401
1978	14.11403
1979	19.23153
1980	22.96195
1981	22.56056
1982	30.42847
1983	35.39334
1984	50.46788
1985	54.22212
1986	59.2395
1987	54.20673
1988	61.4008
1989	49.77943
1990	81.34394
1991	57.6499
1992	58.86872
1993	52.45013
1994	45.28445
1995	64.45568
1996	39.94445
1997	44.84293
1998	44.9391
1999	116.90865
2000	60.06708
2001	82.22601
2002	54.42949
2003	44.05238
2004	73.07873
2005	85.8418
2006	66.90983
2007	51.4281
2008	57.04057
2009	50.54667
2010	55.67433
2011	41.66423
2012	64.39563
2013	69.84644
2014	66.42093
2015	58.1634
2016	43.5904
2017	45.93718
2018	67.90056
2019	45.40695
2020	116.87786
2021	60.03009