Year	years
1960	32.682
1961	33.068
1962	33.52
1963	33.949
1964	34.457
1965	34.929
1966	35.445
1967	36.042
1968	36.48
1969	36.835
1970	37.467
1971	37.937
1972	38.429
1973	38.904
1974	39.358
1975	39.829
1976	40.256
1977	40.665
1978	41.025
1979	41.463
1980	41.728
1981	41.957
1982	42.178
1983	42.432
1984	42.616
1985	42.595
1986	42.552
1987	42.885
1988	42.901
1989	42.935
1990	42.996
1991	42.297
1992	42.352
1993	42.358
1994	41.588
1995	41.187
1996	42.577
1997	42.569
1998	40.975
1999	39.117
2000	44.097
2001	44.695
2002	45.557
2003	46.181
2004	46.881
2005	47.587
2006	48.739
2007	49.656
2008	50.765
2009	51.852
2010	52.863
2011	53.766
2012	54.55
2013	55.338
2014	55.422
2015	56.151
2016	57.235
2017	57.491
2018	58.419
2019	58.941
2020	58.404
2021	58.758
2022	59.115