Year	years
1960	36.525
1961	37.21
1962	37.868
1963	38.407
1964	39.067
1965	39.682
1966	40.359
1967	40.939
1968	41.627
1969	42.243
1970	42.936
1971	43.61
1972	44.36
1973	45.188
1974	46.062
1975	46.866
1976	47.671
1977	48.502
1978	49.112
1979	49.819
1980	50.36
1981	50.693
1982	50.88
1983	51.117
1984	51.163
1985	51.298
1986	51.279
1987	51.218
1988	51.056
1989	50.926
1990	50.609
1991	50.304
1992	50.109
1993	49.899
1994	49.665
1995	49.521
1996	49.444
1997	49.617
1998	49.439
1999	49.537
2000	49.464
2001	49.547
2002	49.707
2003	49.745
2004	50.306
2005	50.822
2006	51.392
2007	52.02
2008	52.629
2009	53.297
2010	53.936
2011	54.398
2012	55.073
2013	55.581
2014	56.234
2015	56.677
2016	57.13
2017	57.348
2018	57.846
2019	58.162
2020	57.86
2021	57.4
2022	57.686