Year	base year varies by country
1960	0.504470849199556
1961	0.5023624617456046
1962	0.5407439029305569
1963	0.5796255694018971
1964	0.5918339672270353
1965	0.5855791146693865
1966	0.5717670013070448
1967	0.5819805183763815
1968	0.6054490450750637
1969	0.6225861828676946
1970	0.6357333746611811
1971	0.643261979920683
1972	0.6948990778226507
1973	0.7262139873089537
1974	0.854820510578372
1975	0.9996851379279621
1976	1.028348624539325
1977	1.1371104344657161
1978	1.1490280211715613
1979	1.276694044030316
1980	1.4539554083446746
1981	1.5592540470585206
1982	1.6763856046051657
1983	1.7869666753196616
1984	2.219131886625433
1985	3.070552633955444
1986	3.358793733283371
1987	3.843230832194075
1988	5.516414868455347
1989	6.818774796961493
1990	10.259478310624418
1991	20.822785042736484
1992	21.98225811231575
1993	23.077801772237553
1994	25.416939066213224
1995	27.870280134654664
1996	28.893046073057437
1997	31.62382401706164
1998	33.68085929370637
1999	34.97223544308869
2000	37.49295121869468
2001	39.757802483599505
2002	42.50930833526342
2003	56.73357782956824
2004	82.35804149202941
2005	87.1193672832795
2006	92.90517770912562
2007	100
2008	110.39168751391848
2009	114.25335053980912
2010	120.47263263641213
2011	130.18363660628836
2012	136.82063474236844
2013	143.24137968019198
2014	149.4312535744877
2015	153.12502377699673
2016	156.17784439984416
2017	162.7082257936723
2018	169.41422853961006
2019	173.69298590232214
2020	181.8973810731433
2021	196.04382799963983
2022	217.04826887539986
2023	230.99127559931566