Year	base year varies by country
1980	4.337242227022445
1981	4.903173330689407
1982	5.607181148660286
1983	6.432823359035631
1984	6.9191626668669945
1985	7.636145247590193
1986	8.646767718769453
1987	10.250007865735856
1988	11.808729412663611
1989	13.40050183251449
1990	16.644149282502852
1991	17.81034338479965
1992	20.19836528600133
1993	21.303789749821203
1994	25.036235630078785
1995	27.341666125501135
1996	30.13951872146964
1997	32.62058830525693
1998	35.28688324996513
1999	37.421354141330646
2000	40.341862132267714
2001	44.10014886359887
2002	48.25612349472802
2003	51.118396847691905
2004	52.82124435144977
2005	55.28290383795049
2006	58.02437667425032
2007	65.49985791590983
2008	69.58980169603353
2009	73.89202741202078
2010	76.77887253465599
2011	79.13750040494574
2012	89.04658115251077
2013	92.81945678800463
2014	98.38518536055203
2015	100
2016	103.6292025273836
2017	110.70337619390133
2018	116.55233759601664
2019	116.34108610701132
2020	121.92537380649206
2021	124.29138803019306
2022	126.32671091647623
2023	130.51940450185867