Year	base year varies by country
1960	4.12414369012187
1961	4.247458203831838
1962	4.375086669571378
1963	4.506948157285754
1964	4.637928090890069
1965	4.780723765684625
1966	4.782712700902546
1967	4.841432543802775
1968	5.121935461499155
1969	5.216891937164992
1970	5.372921261522399
1971	5.322357028824572
1972	5.456034222341333
1973	6.17775673617317
1974	7.82685770397758
1975	8.164504718537238
1976	9.652320229190238
1977	12.42748698703576
1978	12.978435343580152
1979	13.827406341109311
1980	17.16585068067228
1981	17.676876537695986
1982	19.144290199004903
1983	20.87623238142421
1984	24.615143867062432
1985	24.69973554796539
1986	24.20070089645125
1987	23.21447228772385
1988	23.1260423235453
1989	22.891912762355688
1990	21.85644892892814
1991	22.001464121750928
1992	21.996219602547896
1993	23.34990969354147
1994	34.18101501709524
1995	37.95589448465668
1996	59.3189052191571
1997	61.645080783850915
1998	64.9661240652394
1999	64.46204415852021
2000	65.49409262922522
2001	69.99744600256832
2002	73.20482512141392
2003	75.60456764188666
2004	73.71191501232686
2005	74.60761424636775
2006	75.62193330662257
2007	77.95755410860922
2008	82.14616163740031
2009	83.13830597113157
2010	84.39886386814011
2011	89.21746550477886
2012	88.8569391891795
2013	91.41311379669074
2014	95.44199353842411
2015	100
2016	98.82016756434304
2017	97.79078036228998
2018	99.43559827941894
2019	101.4077566963298
2020	103.26187897573116
2021	107.32020648010445
2022	109.55879715285295
2023	112.28152729419423