Year	base year varies by country
1973	14.1916266419883
1974	16.3507299584968
1975	16.7000505068571
1976	17.2822116856578
1977	18.1897963919281
1978	19.6010439679483
1979	23.4861586664449
1980	27.2105743975153
1981	30.3143948733214
1982	33.1651778021305
1983	35.0487852406528
1984	37.1912598511608
1985	37.948689681392
1986	40.5619838588703
1987	44.3027087459546
1988	48.7428241003341
1989	53.5791444423245
1990	57.7768490566676
1991	62.4311742999872
1992	67.7285258291423
1993	72.8392370456174
1994	78.8199032561679
1995	84.2799531391493
1996	88.7250186435745
1997	93.40347506621
1998	93.0615228422182
1999	89.8258921716821
2000	87.4487042299336
2001	85.7509959439808
2002	81.3381513106944
2003	78.0302735575486
2004	77.9873013952632
2005	78.9961946585328
2006	80.2473582675892
2007	82.1090027194642
2008	84.2460629219756
2009	83.4463292946252
2010	85.2836125262394
2011	89.2606642455608
2012	93.0707107376443
2013	93.7331262926254
2014	96.6825503896899
2015	98.7133255074363
2016	100
2017	102.875445162364
2018	106.252496981199