Year	base year varies by country
1960	0.03187216619270249
1961	0.03449504411802881
1962	0.036788287097190835
1963	0.045330755278337985
1964	0.05273774602472115
1965	0.05727555454513049
1966	0.06593982660776496
1967	0.07301529101986454
1968	0.07920142098725963
1969	0.08588970979300914
1970	0.09609839256623796
1971	0.10648413080085307
1972	0.12029758318200326
1973	0.1445508984861183
1974	0.1812337968280332
1975	0.22256772204912656
1976	0.2792280293389374
1977	0.3606308659512666
1978	0.4222984965055706
1979	0.5238216967113422
1980	0.668479961405661
1981	0.8206652891869657
1982	1.0239150077212635
1983	1.2328200422704043
1984	1.5062623224440332
1985	1.881073228535438
1986	2.429762093483463
1987	2.9977660355830698
1988	3.8296477965516393
1989	4.7750276104144
1990	7.274090986911097
1991	9.238515562387985
1992	11.332368293352648
1993	14.147507433700005
1994	17.273594190500273
1995	20.52983204819863
1996	23.992881882829497
1997	28.033247906552344
1998	32.17461234978458
1999	36.23599462984896
2000	48.438600079273655
2001	51.596045178733455
2002	54.67539548253224
2003	58.40918635508202
2004	62.663146909971346
2005	65.64164916976301
2006	69.45389354518716
2007	73.06690857130174
2008	78.67653492660699
2009	81.87412669600516
2010	84.98932283164426
2011	90.41742376882044
2012	93.68751010310423
2013	95.47476465326717
2014	97.60922940317724
2015	99.99999999999987
2016	105.14833430514578
2017	110.54637209123564
2018	115.66530992683897
2019	120.2949533830218
2020	122.07739332436715
2021	131.60200961552255
2022	151.16672049104287
2023	160.76238099001014