Year	constant 2015 US$
1970	21880.440075268136
1971	22213.413104137875
1972	23034.840581559183
1973	24508.742984273744
1974	23064.366756658237
1975	23209.051842572284
1976	24646.168741729092
1977	25205.81790931947
1978	26156.040643803168
1979	26469.356201002418
1980	25485.25538391701
1981	24753.381102160834
1982	25341.09162895158
1983	26150.402894192186
1984	27081.86452946747
1985	28156.104736751382
1986	30178.490890169745
1987	30318.197213277766
1988	29920.087661335303
1989	29821.18960559624
1990	30158.396789749288
1991	30307.378651938823
1992	31219.80574267813
1993	31122.629384813554
1994	32739.56504244346
1995	33697.794970237956
1996	34601.214418042146
1997	35515.80685414543
1998	36350.219283556034
1999	37226.10427071623
2000	37894.38879584585
2001	38330.5393454974
2002	38442.946645199365
2003	38555.371346136424
2004	40077.71306012685
2005	41635.29719338274
2006	43286.266586070196
2007	42813.37871493877
2008	42298.29416615883
2009	40335.58776981075
2010	42083.25734269176
2011	42228.181156898194
2012	42423.82345312386
2013	43609.647201795015
2014	44941.273066601934
2015	45798.02980231928
2016	46515.59644210198
2017	47465.47872057831
2018	48205.06005766638
2019	48603.873403913596
2020	48201.61984853501
2021	51061.71682230767