Year	base year varies by country
1960	15.099146669629867
1961	13.389856382890972
1962	12.051705560717016
1963	14.183100960922198
1964	16.243590854744074
1965	16.73001790158859
1966	17.08421813996595
1967	17.165058517924553
1968	17.031987183675
1969	19.612027105528167
1970	16.878820357872637
1971	15.278881985210932
1972	16.82963438923584
1973	18.04094465936982
1974	27.508752834341994
1975	29.042593835221147
1976	31.799814514771164
1977	37.956486948726
1978	38.825651497308684
1979	44.4998111740219
1980	54.12765334430467
1981	62.512809456940474
1982	56.77277450953597
1983	49.026228630316744
1984	47.10373620322135
1985	45.954339264460586
1986	39.66299519122713
1987	36.21191243275398
1988	32.006332912180135
1989	33.72442595387378
1990	35.68503902952242
1991	38.14349569702114
1992	39.784897828861496
1993	40.835923678208836
1994	46.96487285611728
1995	49.41763833967375
1996	50.15403765661043
1997	53.66791632239557
1998	51.63783119558655
1999	38.05708529250295
2000	33.61070443577434
2001	42.550552464079026
2002	47.43814823466461
2003	52.77364951749035
2004	56.14621290312268
2005	60.96523745465523
2006	66.27932470313262
2007	70.96091291805642
2008	81.67183543441426
2009	79.41023944637267
2010	86.56805400562455
2011	92.48715528513517
2012	97.11450584860127
2013	99.7044208293781
2014	101.75131322141888
2015	96.17978508603015
2016	97.30618935295422
2017	98.21311384109252
2018	100
2019	99.94342481273073
2020	98.1185014084462
2021	100.12896012647394
2022	102.32750280126461
2023	101.9098051499166