Year	current US$
1960	0.634103031050276
1961	0.6988191948689939
1962	0.6523762340708052
1963	0.7235317634232729
1964	0.5282330000919793
1965	0.6409359784347504
1966	0.6812861267830209
1967	0.6289176279961952
1968	0.5787642483576372
1969	0.6706052062779438
1970	0.6114582452175997
1971	0.666734041731999
1972	0.7541725160473788
1973	0.8086254004329585
1974	0.8433558852457497
1975	1.2660343124514797
1976	1.4893941852562613
1977	1.8503756884069609
1978	1.5891673754113205
1979	2.0996343174978827
1980	1.9573805560236166
1981	2.0626652763685325
1982	1.7208692312458782
1983	2.1595215008994644
1984	2.0299627577380446
1985	2.564362371374003
1986	2.7699207697445023
1987	2.181198069958125
1988	2.0000855047484416
1989	2.071876914488075
1990	2.527006132581193
1991	2.672959525097643
1992	2.917079963999886
1993	2.4711667954706824
1994	2.3666811444556966
1995	1.7120815894139279
1996	3.1581988078310044
1997	1.2276460344634355
1998	1.5011237324528504
1999	0.8748387890042555
2000	0.4142247318123636
2001	0.42983650824548464
2002	0.4307777771744092
2003	0.45120723826442355
2004	0.44287613894692307
2005	0.4081501282845044
2006	0.4763302384982335
2007	0.33135364165880793
2008	0.5421007221741196
2009	0.42327735060232025
2010	0.5309516855879934
2011	0.36487390388939156
2012	0.3022989725666917
2013	0.23360161684931507
2014	0.2516796388465233
2015	0.11685265239287809
2016	0.23184557359847646
2017	0.18657707613080687
2018	0.14339335182880286
2019	0.18989726221701358
2020	0.1801785049547051
2021	0.19391018609355715
2022	0.26121458998676106