Year	current US$
1970	1648.223204860145
1971	1848.6808054595654
1972	2214.597253526488
1973	2848.6574348326812
1974	3173.222995237406
1975	3655.892810339327
1976	3810.194802952705
1977	4282.843409122732
1978	5205.291705786234
1979	6253.148055961521
1980	6915.303655228911
1981	5934.423077691923
1982	5667.50219202114
1983	5504.322676984047
1984	5297.640769754045
1985	5444.187941860007
1986	7652.6821865508045
1987	9463.926251411842
1988	10372.599169768691
1989	10548.44834810034
1990	13124.933584819964
1991	13515.825371959136
1992	14790.55857399044
1993	13386.969171844647
1994	14158.518810054997
1995	16420.68286115075
1996	16679.343592753983
1997	15268.07444948568
1998	15711.514751420058
1999	15626.946117675443
2000	14275.46123841144
2001	14423.498283998752
2002	15640.465669131549
2003	19149.51678244119
2004	22019.60677942608
2005	22904.21296931042
2006	24423.63480601797
2007	28090.576125070573
2008	30687.617139149497
2009	27620.790552851257
2010	27268.15520399736
2011	29591.34643812145
2012	27395.33228692397
2013	28581.238943573517
2014	29200.263609605638
2015	25112.44647911059
2016	25764.675762526913
2017	27373.34950773231
2018	29635.09753344303
2019	28975.58833301436
2020	27865.609783639135
2021	31457.712851604647