Year	years
1960	53.519
1961	53.618
1962	53.633
1963	53.467
1964	53.479
1965	53.436
1966	53.533
1967	53.689
1968	54.036
1969	54.324
1970	54.715
1971	55.111
1972	55.594
1973	56.124
1974	56.333
1975	57.215
1976	57.989
1977	58.634
1978	59.398
1979	60.174
1980	60.952
1981	61.836
1982	62.42
1983	62.955
1984	63.5
1985	63.95
1986	64.348
1987	64.388
1988	64.458
1989	64.109
1990	63.928
1991	63.438
1992	62.923
1993	62.3
1994	62.331
1995	60.879
1996	59.157
1997	57.218
1998	55.12
1999	52.92
2000	50.916
2001	49.02
2002	47.743
2003	46.633
2004	45.93
2005	45.428
2006	45.302
2007	45.619
2008	46.075
2009	46.107
2010	48.176
2011	49.261
2012	50.486
2013	51.753
2014	52.807
2015	53.86
2016	55.096
2017	55.9
2018	56.591
2019	57.053
2020	57.537
2021	55.927
2022	55.923