Year	current US$
1970	2.9108003330037877
1971	3.4047003259747175
1972	4.457835382300392
1973	6.882916004877926
1974	10.654951729526791
1975	13.475567219230909
1976	11.496405437189166
1977	13.73800919055243
1978	16.54442284590121
1979	22.467182646223257
1980	24.745656277043913
1981	22.499877835966725
1982	21.498118820726827
1983	19.18981715284797
1984	18.838688970779184
1985	20.15371100526893
1986	23.98886841171188
1987	27.099164723957813
1988	27.29089660760628
1989	26.79799075184613
1990	32.568367761046744
1991	31.85608032203846
1992	30.807851567624972
1993	27.53973150037493
1994	30.86292731090088
1995	30.002943836627203
1996	24.381283189149176
1997	21.12078933872559
1998	21.18852808492935
1999	20.17108882172288
2000	18.97886351397366
2001	21.296085224378206
2002	25.536539210224902
2003	32.736900600598915
2004	34.35826286901936
2005	33.95517966174984
2006	36.69412997712899
2007	42.140887404537196
2008	46.57100737653631
2009	50.41804898509234
2010	51.600617679150076
2011	52.40842012285604
2012	52.954793049257454
2013	56.48670791522185
2014	51.43835360965003
2015	50.68428890774692
2016	52.50627368288328
2017	58.00907860961865
2018	61.212164782681256
2019	58.79977767005457
2020	70.09624094580096
2021	63.49248454075071