Year	base year varies by country
1988	4.332793633776508
1989	4.773965386019639
1990	5.414181597174326
1991	6.245813252293621
1992	7.393641509810153
1993	8.555729591311914
1994	12.364836692880559
1995	12.968716944012579
1996	12.900719453112153
1997	14.230312807099036
1998	16.323901256127666
1999	21.414452530950157
2000	26.246046536692596
2001	30.168066103324108
2002	33.194254163467996
2003	41.46758655004824
2004	48.44385150250102
2005	54.64358601487359
2006	60.2340272660861
2007	64.26140346057988
2008	71.72850259021537
2009	77.90405524805468
2010	85.77160604765649
2011	92.76217589502286
2012	99.99997779213736
2013	105.21344428250356
2014	109.86397392485313
2015	112.11348223296247
2016	124.82441540334878
2017	140.1619351613325
2018	151.90661954611465
2019	176.884617981262
2020	224.211347494735
2021	258.2905329393416
2022	327.4083388540435
2023	420.413864795504