Year	years
1960	38.108
1961	38.744
1962	39.402
1963	39.955
1964	40.606
1965	41.177
1966	41.819
1967	42.419
1968	43.021
1969	43.643
1970	44.325
1971	44.992
1972	45.724
1973	46.556
1974	47.506
1975	48.346
1976	49.291
1977	50.184
1978	50.927
1979	51.682
1980	52.27
1981	52.734
1982	52.919
1983	53.171
1984	53.037
1985	53.174
1986	53.202
1987	53.187
1988	53.017
1989	52.876
1990	52.603
1991	52.323
1992	52.138
1993	51.925
1994	51.737
1995	51.61
1996	51.52
1997	51.449
1998	51.108
1999	50.957
2000	50.842
2001	50.81
2002	50.886
2003	50.954
2004	51.363
2005	51.824
2006	52.355
2007	52.97
2008	53.653
2009	54.394
2010	55.023
2011	55.52
2012	56.158
2013	56.748
2014	57.208
2015	57.762
2016	58.06
2017	58.48
2018	58.849
2019	59.319
2020	59.032
2021	58.598
2022	58.916