Year	current US$
1960	1.785930542454705
1961	1.583837785262821
1962	1.8313607685965714
1963	2.4907626917188095
1964	2.868694591145676
1965	2.9099864022238955
1966	2.6220976766158897
1967	2.92897762938534
1968	2.0459773775360772
1969	1.8766737096866057
1970	1.868422353525395
1971	2.1288745784418035
1972	1.7050821328045476
1973	2.1127964326097057
1974	3.0272014260766427
1975	4.519157853073236
1976	4.271286152904985
1977	3.186426978806039
1978	3.6759297745056005
1979	4.224769883159106
1980	5.707226039079278
1981	4.754611692340099
1982	4.651830980477592
1983	4.261455078378228
1984	4.036875714933869
1985	3.840983906605285
1986	4.709610385853263
1987	4.530970998653802
1988	5.111885346726378
1989	5.028384743470631
1990	4.595970972171462
1991	6.165529258162734
1992	4.996911851285249
1993	3.784281000330672
1994	4.908857907169374
1995	3.498497785579505
1996	3.4542749134442103
1997	3.072628546845744
1998	3.1672188202304046
1999	2.7704831393525153
2000	2.5902211985683015
2001	3.8584699602120427
2002	4.36803945495338
2003	3.8088691026907915
2004	4.441773941772053
2005	5.851048590054767
2006	5.5662683541405
2007	5.602846307827456
2008	6.301272887827875
2009	6.975188753810263
2010	8.995281389997313
2011	9.972627612651563
2012	8.268709795606828
2013	8.049696718995483
2014	8.885171609902699
2015	8.842669923678878
2016	7.788638997087167
2017	8.238451983871363
2018	6.639257568605441
2019	8.031441866436406
2020	8.811740269440042
2021	9.462768911353725
2022	8.06175328710755