Year	base year varies by country
1980	3.9922811177277673
1981	4.517040132825001
1982	5.104150526535248
1983	5.45889514077397
1984	6.05513300701454
1985	6.624871929168758
1986	6.962605886916588
1987	7.762905696203372
1988	9.06800892254748
1989	9.381185283316656
1990	12.580820431540582
1991	13.49238571938997
1992	15.267586006029122
1993	17.865917421777418
1994	22.85713458232313
1995	25.037435342370685
1996	28.062931918585637
1997	30.440766563854183
1998	33.83572848461367
1999	36.432478272311315
2000	38.45778298136097
2001	42.267796404931666
2002	47.03522493198783
2003	59.21127186189703
2004	61.43929561160417
2005	68.01287392376938
2006	73.68767845376675
2007	80.53646574430081
2008	85.71428571428571
2009	89.89125164507861
2010	91.46010379705277
2011	95.55461523090845
2012	100
2013	102.3522743375372
2014	106.10888486728713
2015	109.6717803110565
2016	110.05008481295981
2017	112.88572958761381
2018	121.7561484149173
2019	123.26751117734725
2020	121.63308589607635
2021	114.93749412538772
2022	117.25533750665467
2023	121.81704707560628