Year	constant 2015 US$
1970	69132.38473430747
1971	69180.50133752605
1972	67548.72114658778
1973	59420.94243096136
1974	48695.95989778371
1975	40163.01265108427
1976	40149.63347179997
1977	36177.12498282567
1978	36446.099715101256
1979	39066.49341322202
1980	29763.586925861364
1981	22916.620384925685
1982	19246.57709087452
1983	19779.947877531507
1984	19922.113093997723
1985	18315.370860379287
1986	19085.21242547823
1987	19829.9944237061
1988	17160.713689676348
1989	20813.66105824185
1990	20259.600345531435
1991	14944.505631286012
1992	22580.728428765946
1993	29652.017388069187
1994	32399.182129706467
1995	33683.499590261046
1996	32930.46287030541
1997	32630.944340921793
1998	32746.255887453273
1999	31168.883574209638
2000	31662.832520794742
2001	30825.899885776354
2002	30891.31526712963
2003	35309.7927190879
2004	37986.137576040404
2005	40476.31753927507
2006	41161.01551670961
2007	41132.20564911215
2008	39859.894102097154
2009	35123.25596371093
2010	32568.675041992246
2011	33427.82029743869
2012	33009.116507754414
2013	31082.412029404317
2014	30282.54256132365
2015	29315.193101955338
2016	29134.372568520896
2017	27244.487262019997
2018	26664.64879046477
2019	26278.739632541055
2020	25353.240442293838
2021	26452.96877482306
2022	27953.339425362654
2023	27068.486914230885