Year	US Dollars
1960	0.03505
1961	0.8757
1962	2.25096
1963	2.0811
1964	9.02723
1965	8.5958
1966	7.6961
1967	7.00477
1968	8.87902
1969	9.44978
1970	9.6
1971	8.93009
1972	8.0736
1973	10.11926
1974	11.54694
1975	14.54337
1976	15.04335
1977	14.01718
1978	16.82289
1979	19.99908
1980	25.26551
1981	14.27226
1982	15.24678
1983	16.73337
1984	12.78296
1985	11.77831
1986	16.91847
1987	22.5517
1988	38.4608
1989	34.42048
1990	57.62963
1991	50.9246
1992	58.86287
1993	57.34487
1994	115.46638
1995	84.78763
1996	65.13899
1997	29.14814
1998	60.99191
1999	27.39404
2000	20.88851
2001	10.79008
2002	60.36565
2003	14.00385
2004	8.66599
2005	4.81175
2006	12.74308
2007	8.63269
2008	28.87853
2009	116.21229
2010	40.02407
2011	66.67512
2012	132.13339
2013	56.67563
2014	40.2269
2015	27.62119
2016	25.43155
2017	33.36926
2018	37.65947
2019	44.88642
2020	58.25907
2021	56.45556