Year	constant 2015 US$
1970	3124.219026414906
1971	3199.4817860129133
1972	3096.371603040787
1973	3124.4559916440585
1974	3539.266780603356
1975	3921.30380739594
1976	4076.4665203356158
1977	4228.764912302599
1978	4178.552482778576
1979	4029.241617466218
1980	4129.808130191599
1981	4330.525588340632
1982	4201.359906468198
1983	3798.985072875249
1984	3750.9262997790497
1985	3918.03364657009
1986	3802.0449047155776
1987	3655.1057816382445
1988	3309.1695921922983
1989	3175.876153895189
1990	3362.940845275415
1991	3751.9898489166894
1992	3871.786053379145
1993	3567.7996681278064
1994	3653.660872035028
1995	3609.1249955304293
1996	3579.307513363002
1997	3797.120663402625
1998	3844.9496648536533
1999	3315.301164709363
2000	3451.429123023139
2001	3274.890641732713
2002	3540.128519013035
2003	3438.0990697123093
2004	3236.8851655455583
2005	3290.128854694561
2006	3419.2422404213303
2007	3570.558710960159
2008	3927.9163301595418
2009	4177.732358688677
2010	4115.626102883055
2011	4237.671835726687
2012	4355.993598538882
2013	4620.792714777323
2014	4773.815200489765
2015	4875.507360622316
2016	4179.202528912461
2017	4625.398301448855
2018	4404.3748907824565
2019	4355.197102851588
2020	4081.6671499678405
2021	4119.463534108796