Year	constant 2015 US$
1960	709.2591572798796
1961	685.7501190524033
1962	685.921342952376
1963	684.1233899788632
1964	686.7931693520381
1965	664.2574689651061
1966	659.2917034502728
1967	645.0623729295074
1968	677.251283989223
1969	684.1550865721711
1970	708.568330812547
1971	723.668040429856
1972	689.1912132007694
1973	650.5304178837781
1974	611.9276616452916
1975	595.2346920453041
1976	547.2821343975268
1977	555.5103283425408
1978	527.5151477291403
1979	573.1267674094988
1980	555.694079519557
1981	493.2199338883612
1982	471.3820822787545
1983	438.09906184999625
1984	449.9069331958933
1985	455.05862369692386
1986	434.99944644059684
1987	403.0554318296879
1988	395.42105454798696
1989	355.6651535783866
1990	404.0870589140099
1991	365.8580081731176
1992	357.43789696667557
1993	361.5315485360772
1994	350.47445852053113
1995	343.30788066779695
1996	339.2740128192938
1997	343.8970741294031
1998	353.38274517092196
1999	356.8588182813069
2000	358.50240086136375
2001	350.6455278252221
2002	342.3826439957133
2003	363.6407012709209
2004	371.73264271807454
2005	360.6350048534954
2006	356.7898918498193
2007	324.3527114963036
2008	334.37219535821725
2009	333.02355090083387
2010	338.4383648874971
2011	336.67683381036863
2012	337.568332072105
2013	350.8190343841208
2014	332.83880701676435
2015	334.0141392012779
2016	337.70228872563035
2017	332.8749104768941
2018	336.46297023163834
2019	337.9673595659779
2020	336.84767049136536
2021	338.6838608952126
2022	338.9907657043947
2023	339.28444092020993