Year	years
1960	39.936486093579084
1961	40.19358292411599
1962	40.756156123974456
1963	40.921327142313096
1964	41.33880116619938
1965	41.47101140907287
1966	41.47009013368412
1967	41.563347308285515
1968	42.01089265418384
1969	42.24835784776395
1970	42.80482777435395
1971	43.29687498558809
1972	43.417323191667826
1973	44.211278705831134
1974	44.43248112988704
1975	44.81795849190389
1976	45.40526294770107
1977	45.807338130189784
1978	46.024703404197346
1979	46.5120971018203
1980	46.8837313021343
1981	47.22347877827711
1982	47.43363605727974
1983	46.58913154514722
1984	46.523234345850724
1985	46.753686315313914
1986	47.12415713823102
1987	47.33626738834286
1988	46.998559426373305
1989	47.93043182867709
1990	47.79775987291266
1991	47.746964067713606
1992	47.50025205409892
1993	47.7004039847874
1994	48.17167725532849
1995	48.253113078092596
1996	48.20711263175456
1997	48.42095219621785
1998	48.09347554728754
1999	48.87103536639768
2000	49.76667094571204
2001	50.12352093417093
2002	50.48915625930068
2003	51.013229199473315
2004	51.51093555422512
2005	52.11547430633517
2006	52.869201559909236
2007	53.46304769464436
2008	54.04304501344873
2009	54.729215121907195
2010	55.32620664241811
2011	55.9675473932124
2012	56.49453588915654
2013	56.94217539837117
2014	57.36744372358983
2015	57.766494868014306
2016	58.26218431574311
2017	58.657879819470786
2018	59.010982135034304
2019	59.364417392891276
2020	58.902879810440886
2021	58.264335752509766
2022	58.80784964929215