Year	constant 2015 US$
1981	4880.915848957427
1982	4846.841094741792
1983	4964.519401269305
1984	5158.497168131947
1985	5347.4982791041275
1986	5443.062377659729
1987	5490.826824045807
1988	5538.604667657634
1989	5613.48787331047
1990	5722.642156886667
1991	5694.126980231311
1992	5743.5245471280805
1993	5744.760244088548
1994	5910.696033684955
1995	5996.915440035275
1996	6062.507232191699
1997	6209.677101142789
1998	6242.187648553485
1999	6333.477050830537
2000	6464.126776121023
2001	6505.700804050953
2002	6651.1934760198565
2003	6664.110975064597
2004	6928.617870523415
2005	7075.555910314766
2006	7345.871876307239
2007	7617.506428951897
2008	7502.084703301778
2009	7359.46721864197
2010	7642.325149919431
2011	7744.29507065351
2012	7890.076475098948
2013	7982.256618955885
2014	8151.752555473114
2015	8323.816601876424
2016	8459.03397183365
2017	8673.891126966964
2018	8797.833051329651
2019	8898.413935208006
2020	8460.052421056716
2021	8834.201760170648