Year	base year varies by country
1970	4.331394990464448
1971	4.671230653563255
1972	5.069129710809169
1973	5.669792882970304
1974	6.573852771350988
1975	7.677063293829277
1976	8.943000069337687
1977	11.034150052881145
1978	13.310610118992294
1979	15.564321238034875
1980	17.64290736507496
1981	19.82201341391608
1982	22.514308619545595
1983	25.189962020952557
1984	27.926784483651275
1985	30.327221123251164
1986	33.626463482330024
1987	35.62528732444341
1988	37.74004890766848
1989	40.34268085553811
1990	43.298283953321864
1991	46.301084183515414
1992	49.40824296928302
1993	51.65000965243392
1994	53.653956850034014
1995	56.30077148922054
1996	56.74958870096866
1997	58.01406051059714
1998	58.88401258464555
1999	60.49271175216319
2000	77.87925649960334
2001	80.27835439334623
2002	82.87899718825375
2003	85.51246424192888
2004	88.11411597532954
2005	91.10656134475477
2006	94.25628288550882
2007	97.28306641243489
2008	99.49561247057144
2009	99.62708212480318
2010	100
2011	100.19676415203105
2012	100.37166452322599
2013	100.82182360981828
2014	100.73711380268094
2015	101.4025720542156
2016	101.75524551661923
2017	102.91170338910804
2018	103.9536622393787
2019	105.38276885801245
2020	106.55650746205822
2021	109.28388150221599
2022	113.91313604428359
2023	120.58833817202421