Year	constant 2015 US$
1970	22540.783570736083
1971	22850.812365040332
1972	23836.770334326233
1973	24900.442119678526
1974	23598.453738115633
1975	23284.391615511944
1976	24224.259352819765
1977	24949.178427358576
1978	25954.231982302237
1979	25504.95604223124
1980	24691.33843359846
1981	25499.387639619636
1982	25554.19490791674
1983	26132.288652173505
1984	28004.79775648654
1985	28914.92793186998
1986	29652.848501886685
1987	30453.29270769408
1988	31923.576510855386
1989	32356.27733613659
1990	32417.20639728937
1991	32091.46079301061
1992	32746.881098427664
1993	33054.33209470082
1994	34109.93040079641
1995	34835.76202504427
1996	35927.4736334642
1997	37420.88252142933
1998	39174.164357157846
1999	40340.47119403827
2000	41418.23381170892
2001	41634.570070798145
2002	41857.55487188947
2003	42297.26860480593
2004	43518.860378456455
2005	44306.58347038441
2006	45531.81270795742
2007	45245.31058925163
2008	43616.71941161631
2009	42771.43334880154
2010	44247.7128088397
2011	44827.37444087119
2012	46213.21184048223
2013	46541.69085959591
2014	47749.14663903564
2015	49077.96634357062
2016	49239.327231642965
2017	50253.58615159401
2018	51444.109440914086
2019	52369.04685731517
2020	50084.53972761887
2021	52619.392140660835