Year	years
1960	41.625
1961	41.827
1962	42.149
1963	42.447
1964	42.77
1965	43.194
1966	43.55
1967	43.92
1968	44.512
1969	45.047
1970	45.636
1971	45.513
1972	46.593
1973	47.117
1974	47.534
1975	47.97
1976	48.131
1977	48.593
1978	49.06
1979	49.534
1980	49.998
1981	50.29
1982	50.902
1983	51.313
1984	51.789
1985	52.196
1986	52.519
1987	52.935
1988	53.298
1989	53.437
1990	53.524
1991	52.703
1992	51.244
1993	53.868
1994	53.651
1995	54.542
1996	54.459
1997	54.267
1998	54.681
1999	54.759
2000	55.111
2001	55.379
2002	55.759
2003	56.005
2004	56.275
2005	56.492
2006	57.041
2007	57.084
2008	57.514
2009	57.91
2010	58.303
2011	58.507
2012	58.687
2013	59.266
2014	59.285
2015	59.695
2016	59.939
2017	60.354
2018	60.59
2019	60.695
2020	60.071
2021	59.728
2022	60.336