Year	years
1960	39.93648609357908
1961	40.19358292411599
1962	40.756156123974456
1963	40.92132714231309
1964	41.338801166199374
1965	41.47101140907287
1966	41.470090133684124
1967	41.563347308285515
1968	42.01089265418385
1969	42.24835784776395
1970	42.80482777435394
1971	43.29687498558809
1972	43.41732319166781
1973	44.211278705831134
1974	44.43248112988704
1975	44.817958491903894
1976	45.40526294770107
1977	45.807338130189784
1978	46.02470340419734
1979	46.5120971018203
1980	46.8806738989099
1981	47.22017633621742
1982	47.43098169310282
1983	46.58621252962369
1984	46.520368301597244
1985	46.751218414116344
1986	47.12161208079526
1987	47.33389575879372
1988	46.99604051444507
1989	47.928369906871346
1990	47.7957786818314
1991	47.74462567179923
1992	47.497850718473366
1993	47.69824852195038
1994	48.169360210345886
1995	48.250850636020644
1996	48.20485121882879
1997	48.41878255686887
1998	48.09103214892547
1999	48.86872559920244
2000	49.76444514559802
2001	50.121450287015065
2002	50.48721537133312
2003	51.0114648275875
2004	51.50894871204297
2005	52.11378220355674
2006	52.86743422581814
2007	53.46137963690341
2008	54.041573261276675
2009	54.727772443270496
2010	55.32474819979214
2011	55.96636617032434
2012	56.49326496364134
2013	56.940897227289746
2014	57.36636608581231
2015	57.76529468969613
2016	58.26118090726666
2017	58.656774868182374
2018	59.01009544233776
2019	59.36344849069105
2020	58.901632041723715
2021	58.263177180714905
2022	58.806490886159786