Year	years
1960	38.181
1961	38.542
1962	38.928
1963	39.334
1964	39.758
1965	40.184
1966	40.648
1967	41.055
1968	41.522
1969	41.849
1970	42.189
1971	42.581
1972	43.158
1973	43.596
1974	44.085
1975	44.681
1976	45.488
1977	46.176
1978	46.961
1979	47.362
1980	47.877
1981	48.31
1982	48.813
1983	49.333
1984	49.747
1985	50.374
1986	51.075
1987	51.659
1988	52.294
1989	52.684
1990	53.292
1991	53.624
1992	54.089
1993	54.537
1994	54.91
1995	55.295
1996	55.558
1997	55.978
1998	56.218
1999	56.526
2000	56.578
2001	56.66
2002	56.606
2003	56.738
2004	56.826
2005	57.125
2006	57.456
2007	57.675
2008	57.869
2009	57.956
2010	58.363
2011	58.462
2012	58.716
2013	58.965
2014	59.125
2015	59.377
2016	59.539
2017	59.856
2018	60.14
2019	60.454
2020	60.088
2021	59.821
2022	59.954