Year	constant 2015 US$
1970	8773.457278046231
1971	8986.690457766997
1972	9322.621187258103
1973	9736.791870887528
1974	9588.591205616562
1975	9488.679398795299
1976	9799.254376151684
1977	9951.192558897963
1978	10276.91684564067
1979	10501.97888788394
1980	10411.451852635124
1981	10221.16941638981
1982	10255.073729757503
1983	10409.499793145258
1984	10606.664387168417
1985	10824.400418327516
1986	11330.080354376736
1987	11618.068863953595
1988	12058.027375285781
1989	12376.787059543145
1990	12685.311588326105
1991	12834.105737357419
1992	12983.465672746339
1993	12735.725641064364
1994	13004.712633397156
1995	13279.45255353094
1996	13594.998285032218
1997	14044.87350933168
1998	14530.011516289034
1999	15002.222135708847
2000	15539.543591906788
2001	15850.79768195239
2002	16024.024716203021
2003	16298.883671438227
2004	16824.46015717375
2005	17238.02539427835
2006	17806.07551567795
2007	18371.405842240398
2008	18178.260245551854
2009	17290.97994797986
2010	17804.275506613583
2011	18059.388923814287
2012	17979.985812648963
2013	18010.257475931765
2014	18291.485370638133
2015	18574.89375683287
2016	18833.80956258178
2017	19266.641760502134
2018	19575.06974150349
2019	19810.139359412184
2020	18514.240252462096
2021	19426.427681242967