Year	years
1960	42.937
1961	43.1
1962	43.285
1963	43.494
1964	43.747
1965	44.026
1966	44.381
1967	44.756
1968	45.366
1969	45.973
1970	46.45
1971	46.917
1972	47.324
1973	47.978
1974	48.306
1975	48.722
1976	49.236
1977	49.842
1978	50.321
1979	50.907
1980	51.201
1981	51.472
1982	51.528
1983	51.543
1984	51.546
1985	51.556
1986	51.672
1987	51.726
1988	51.843
1989	51.739
1990	51.485
1991	51.306
1992	50.989
1993	50.87
1994	50.797
1995	50.786
1996	50.744
1997	50.624
1998	50.914
1999	51.748
2000	52.362
2001	53.161
2002	53.863
2003	54.895
2004	55.596
2005	56.299
2006	56.911
2007	57.52
2008	58.086
2009	58.894
2010	60.105
2011	61.049
2012	62.03
2013	62.96
2014	63.873
2015	64.651
2016	65.386
2017	65.999
2018	66.535
2019	66.989
2020	66.408
2021	66.201
2022	66.782