Year	US Dollars
1960	1.03162
1961	3.79091
1962	4.41631
1963	2.8339
1964	4.04356
1965	3.32141
1966	2.87349
1967	3.24875
1968	3.17819
1969	2.89798
1970	3.74279
1971	4.41024
1972	4.19028
1973	6.62214
1974	10.35076
1975	18.05424
1976	15.81159
1977	19.40288
1978	23.33517
1979	31.34667
1980	35.01098
1981	35.08031
1982	33.11915
1983	27.76713
1984	25.04852
1985	21.14258
1986	28.32329
1987	37.13451
1988	40.5669
1989	35.53241
1990	44.38485
1991	39.90197
1992	48.37001
1993	33.17396
1994	32.55489
1995	28.50288
1996	27.84809
1997	29.69403
1998	30.69591
1999	29.61035
2000	30.88031
2001	35.99941
2002	34.67146
2003	46.22499
2004	46.25024
2005	37.8415
2006	46.53734
2007	67.69049
2008	54.37606
2009	71.14074
2010	65.62349
2011	52.60747
2012	59.0596
2013	69.7053
2014	52.16065
2015	49.19245
2016	42.60686
2017	45.95231
2018	42.26513
2019	35.50757
2020	36.89292
2021	40.37769