Year	current US$
1971	954.9798041866168
1972	736.2845595169165
1973	1247.830384222763
1974	1359.7754772065764
1975	1142.4705995261436
1976	1173.8583886889774
1977	1312.3598730038836
1978	1555.8360184587775
1979	2283.3813200380823
1980	3115.8984086330156
1981	3502.280915668243
1982	2845.645394904759
1983	1536.854140003705
1984	1428.7961801143322
1985	1392.1902840794414
1986	1794.296684511133
1987	2282.259665503152
1988	2527.8358705707005
1989	2569.8004184800875
1990	2819.5458968934704
1991	3438.2831375634296
1992	3975.59781841041
1993	4610.768782072845
1994	5346.254238638535
1995	5852.563668981735
1996	6212.561758392944
1997	7243.383140206449
1998	7622.525417447543
1999	7160.846180089285
2000	6755.67767113875
2001	6155.1391212043
2002	4010.684849493156
2003	3380.465194811827
2004	3839.916705766882
2005	4959.252344804855
2006	5629.846251658258
2007	6737.056265640224
2008	8641.749363884997
2009	8875.751381053815
2010	11194.0514133489
2011	13238.785776969555
2012	13326.152591336355
2013	15207.282794932034
2014	14854.510423790784
2015	14048.43555798074
2016	14949.304682776088
2017	16557.20878355447
2018	16444.15473848672
2019	15768.940290790131
2020	13661.846748420863
2021	14591.58202594587