Year	years
1960	46.507799182263
1961	46.990265941934986
1962	47.41432278244557
1963	47.82396199543596
1964	48.266580738264125
1965	47.07495949373008
1966	48.17651977038077
1967	48.83075881522708
1968	49.888177044373734
1969	50.293712357492474
1970	50.26447438712043
1971	49.265249375952905
1972	51.45050004327378
1973	51.87067464464908
1974	52.329205817378515
1975	52.729628812930414
1976	53.195817893392835
1977	53.67316852103929
1978	54.06350476505038
1979	54.5616229017384
1980	55.04014402460724
1981	55.367722227181865
1982	55.792168139782284
1983	56.201120126132906
1984	56.77947030844992
1985	57.29064187167086
1986	57.72935322190797
1987	58.316468744817286
1988	58.66328141794549
1989	59.11971981035735
1990	59.45280724282823
1991	59.75357532721556
1992	60.23079951277902
1993	60.52278603959702
1994	60.803881177908494
1995	61.22052503859856
1996	61.55184004155298
1997	61.89534333871077
1998	62.31423755725849
1999	62.70297504192785
2000	63.04447753193175
2001	63.3218116291105
2002	63.700763698609826
2003	63.94031129989144
2004	64.1473272847909
2005	64.52305032168894
2006	64.83784029045502
2007	65.0789893650566
2008	65.24617143816523
2009	65.61670534529732
2010	65.93956811812521
2011	66.3346744488031
2012	66.6761676514565
2013	67.03811040058973
2014	67.51672543977388
2015	67.93024729156122
2016	68.26989527892887
2017	68.5867520062649
2018	68.82272652272779
2019	69.0189296487657
2020	67.94165287915334
2021	66.37729584441517
2022	67.2367027313421