Year	current US$
1970	0.942736385401473
1971	0.9377773190935809
1972	1.0042342961659714
1973	0.9558633200240592
1974	1.3697857137967084
1975	1.331579701141365
1976	1.1875751095442513
1977	1.685669448002619
1978	1.8227117792688559
1979	1.939239230961827
1980	2.520740965458826
1981	2.8781334816906803
1982	2.4765592943896944
1983	2.264191117287591
1984	2.298814412655907
1985	2.6251790214339334
1986	2.651166355865362
1987	3.0515498046552585
1988	3.2568891129686337
1989	3.4225913506192844
1990	4.367835384779374
1991	4.422825253534897
1992	4.5317458708048655
1993	4.464159367670104
1994	4.860560697031676
1995	5.08335665496507
1996	4.475088579365941
1997	4.004364873615363
1998	4.769958087781362
1999	5.195190393718234
2000	4.335922334191721
2001	4.172073373103615
2002	4.618044095701866
2003	4.328583112240177
2004	4.845386616369045
2005	4.877156232473794
2006	5.419553961769868
2007	5.631533073177623
2008	6.139837311341173
2009	6.252422357556257
2010	5.384765830440472
2011	6.1391613640633205
2012	6.673020504928887
2013	6.04194746527244
2014	6.594995131089092
2015	5.561680026925843
2016	5.316987676634564
2017	5.582686189218101
2018	4.272253582277307
2019	3.518618747502775
2020	5.709809648894007
2021	5.22060846416056