Year	current US$
1970	1.4390091587280658
1971	1.5240760558805828
1972	1.4222921403817754
1973	1.7778288777957512
1974	2.338582667771263
1975	3.0357786159207425
1976	2.9213861817865254
1977	2.7825356949515214
1978	3.237597654331326
1979	3.367864251268762
1980	4.168055914071674
1981	4.142397522075834
1982	3.6520133076719787
1983	3.4360908740603917
1984	3.3642937211368724
1985	3.5259656006662876
1986	3.8315165607943222
1987	4.177681904942548
1988	4.335022814461985
1989	4.426662632412107
1990	6.705379316941505
1991	7.231763171995321
1992	6.308386342042849
1993	5.529771020551774
1994	5.806675550865367
1995	5.691672800529705
1996	5.302148196779364
1997	4.499708546723118
1998	4.860208374908599
1999	5.306299249941922
2000	4.618219284519417
2001	4.5782865685781395
2002	4.8004400338407125
2003	5.209904487330522
2004	5.707106294753201
2005	10.540021880051784
2006	7.271707252860737
2007	7.287342009213059
2008	8.448703809252896
2009	6.6735422777994335
2010	6.055933146239654
2011	6.980501535301835
2012	6.565100790859129
2013	7.372585399787468
2014	7.613301722694031
2015	6.573356764100516
2016	6.861068331499443
2017	6.63270169877718
2018	5.940565295103766
2019	5.113240382664943
2020	7.111208617493077
2021	8.071056729103221