Year	current US$
1971	860.4346553201556
1972	868.62759557178
1973	1152.8442205670106
1974	1377.5892078014826
1975	1352.8476670860198
1976	1234.2143513961398
1977	1307.7382686927988
1978	1447.903843586798
1979	1685.9805723639888
1980	2270.4254987154227
1981	2329.973673888183
1982	2071.03915872429
1983	2266.987401034631
1984	2009.7333132940446
1985	1397.9416315658796
1986	1544.749371846953
1987	2023.1791201407652
1988	2130.773060156248
1989	2154.585938482339
1990	2456.5119995027453
1991	2626.5480804934687
1992	2847.758200774723
1993	2832.2055304697847
1994	2914.0177016497096
1995	3234.5965304536776
1996	3018.4019311991333
1997	3101.648803126409
1998	2772.4693608913044
1999	2712.7433883251997
2000	2675.913483925796
2001	2328.956999017991
2002	2226.471316607819
2003	3414.5364429183173
2004	4396.559362377796
2005	4929.038101278151
2006	5096.69260788712
2007	5390.820498041547
2008	4818.7954118049365
2009	5259.491888710313
2010	6522.002250377035
2011	7006.261414482549
2012	6591.845946240734
2013	5977.137238300563
2014	5646.961218287229
2015	5127.603775714905
2016	4681.677958252179
2017	5505.776036423234
2018	5740.363782564608
2019	5449.04868623949
2020	4658.248020380081
2021	5717.12039642913