Year	years
1960	46.107
1961	46.866
1962	47.624
1963	48.274
1964	48.71
1965	48.775
1966	48.676
1967	48.402
1968	48.193
1969	48.248
1970	48.77
1971	49.657
1972	50.349
1973	51.465
1974	51.915
1975	51.744
1976	50.891
1977	49.516
1978	47.913
1979	46.063
1980	41.162
1981	39.578
1982	43.786
1983	44.427
1984	47.952
1985	50.876
1986	51.848
1987	54.005
1988	56.436
1989	52.864
1990	57.017
1991	58.731
1992	59.634
1993	60.175
1994	60.789
1995	61.355
1996	62.207
1997	63.149
1998	63.916
1999	64.832
2000	65.35
2001	65.159
2002	65.628
2003	65.468
2004	65.574
2005	65.642
2006	65.965
2007	66.332
2008	66.705
2009	66.957
2010	67.245
2011	67.289
2012	67.26
2013	67.146
2014	66.993
2015	66.834
2016	66.762
2017	66.908
2018	67.352
2019	68.009
2020	66.432
2021	66.078
2022	66.837