Year	US Dollars
1960	2.70421
1961	2.70845
1962	3.56557
1963	2.35711
1964	2.62588
1965	2.27884
1966	2.58986
1967	2.29735
1968	2.29158
1969	2.74821
1970	3.18885
1971	2.99162
1972	3.75084
1973	1.98724
1974	1.53386
1975	4.41908
1976	1.73845
1977	1.35174
1978	3.10896
1979	3.63217
1980	8.5328
1981	10.0018
1982	9.46322
1983	9.60789
1984	11.08706
1985	11.93437
1986	12.36924
1987	18.71453
1988	23.74809
1989	30.33143
1990	37.70478
1991	36.50024
1992	38.55714
1993	31.34107
1994	37.36493
1995	40.32527
1996	31.7597
1997	37.18254
1998	29.20002
1999	26.10394
2000	35.63302
2001	33.4745
2002	28.69358
2003	38.08462
2004	45.02454
2005	42.77195
2006	55.23294
2007	58.66222
2008	53.86422
2009	56.86745
2010	52.2588
2011	47.24088
2012	47.92361
2013	48.11223
2014	44.9597
2015	43.71066
2016	45.48845
2017	50.13596
2018	46.8643
2019	47.25526
2020	69.49211
2021	54.8548