Year	base year varies by country
1976	13.1457219007105
1977	14.0428223082467
1978	13.7840917182251
1979	14.3665181798539
1980	14.5292357366549
1981	17.3599556470847
1982	19.6827860046911
1983	20.8513075280319
1984	19.6341058246324
1985	20.4033641458735
1986	21.7622775154548
1987	19.9559190942729
1988	20.3768029144727
1989	21.164599244458
1990	28.3576708588781
1991	33.9157822549561
1992	34.856280359864
1993	35.5749211191673
1994	36.6657307461661
1995	38.0759668357187
1996	39.8825100753331
1997	39.9371830188878
1998	42.0889414562677
1999	41.7063411113948
2000	42.2601668431917
2001	42.8723418419633
2002	43.5954137278451
2003	46.2714896187658
2004	49.5947318070397
2005	51.3930844467612
2006	56.4483087447823
2007	59.5987504677824
2008	64.7493685835265
2009	65.4241763279216
2010	77.3351739650191
2011	86.327512689212
2012	88.9030839362824
2013	94.1625805020148
2014	98.6448636218246
2015	96.9419771276367
2016	100.000143742506
2017	99.9523122086516
2018	103.499891353293