Year	current US$
1960	0.39219183427486254
1961	0.8152464922703073
1962	0.7873434589175062
1963	0.7070855944522425
1964	0.5785239358505391
1965	0.6769411000293432
1966	0.7964755312207545
1967	0.8168299159435832
1968	0.8817512344381856
1969	0.7998163560543006
1970	0.9025250497498805
1971	0.9561390452212166
1972	0.9036556705314044
1973	0.8949047528940018
1974	0.9612707016040956
1975	1.091961366450773
1976	1.0953628648916054
1977	0.9551419072704642
1978	1.2807889429980734
1979	1.7596861764558982
1980	2.166102618940268
1981	2.537886724791017
1982	2.4242319675120783
1983	2.250070503410707
1984	2.3205303662453587
1985	2.3683138536667823
1986	2.6336484665566537
1987	3.4425249960796678
1988	3.6004604832292304
1989	3.894222798475395
1990	4.517846266608859
1991	5.164633999638909
1992	4.580983333698338
1993	5.0071906255251415
1994	5.059536453849719
1995	5.6787191920521884
1996	4.775121158374785
1997	4.081675008403396
1998	4.650578029979038
1999	5.663576604631712
2000	4.773466027077238
2001	4.726618241968031
2002	5.264169954825046
2003	5.453218831021487
2004	6.330588557489563
2005	14.159406117962217
2006	8.789107443887955
2007	8.676070225889728
2008	10.261224266690203
2009	7.602467126413035
2010	6.714763012450754
2011	7.979699417987023
2012	6.654062699945852
2013	6.438046598257419
2014	6.399695647236241
2015	5.81523747089727
2016	7.145828356455406
2017	6.486179957211771
2018	6.248143049193114
2019	4.8133913274304945
2020	7.285180096036273
2021	6.868628979305645
2022	6.832594922736803