Year	base year varies by country
1980	4.210558153775161
1981	4.36490568561823
1982	5.106036455239776
1983	5.786410804438788
1984	6.523296087877446
1985	8.084702602308644
1986	8.899877739091574
1987	9.736461615575118
1988	11.698611902181808
1989	13.461903073050472
1990	14.321898015476744
1991	15.179335603755531
1992	16.73796332229862
1993	18.472342153259273
1994	22.25161583756093
1995	23.738359294923736
1996	27.340935510302987
1997	29.285742959126154
1998	31.70754353196612
1999	33.85898157454683
2000	37.67865616916953
2001	41.90008401894743
2002	46.09160153113452
2003	46.67747550652556
2004	47.62981400900108
2005	50.29616985578122
2006	55.02732223389039
2007	60.1373983570135
2008	66.72930660210052
2009	71.36392672489306
2010	74.02287419949981
2011	76.8467553301315
2012	85.49993703213009
2013	88.95395570230296
2014	96.27921770502137
2015	99.99999965757799
2016	107.96867164255062
2017	118.67812546619223
2018	123.93376802030909
2019	125.08178960986179
2020	130.87499127675082
2021	132.88304596229838
2022	141.451149363491
2023	150.52329480776635