Year	years
1960	56.2
1961	56.6
1962	57
1963	57.4
1964	57.8
1965	58.2
1966	58.6
1967	59
1968	59.4
1969	59.8
1970	60.2
1971	60.6
1972	61
1973	61.4
1974	61.8
1975	62.2
1976	62.6
1977	63
1978	62.95
1979	62.9
1980	62.85
1981	62.8
1982	63.7
1983	66.1
1984	64.6
1985	65.4
1986	65.6
1987	66.5
1988	65.6
1989	66.5
1990	67.9
1991	66.7
1992	68.2
1993	67.9
1994	67.6
1995	68.4
1996	69.9
1997	69.3
1998	71.4
1999	70.9
2000	71.7
2001	72.1
2002	71.2
2003	72.1
2004	72.3
2005	72.6
2006	73.1
2007	73.6
2008	73.9
2009	74.2
2010	74.5
2011	73.9
2012	74.2
2013	74.3
2014	74.7
2015	74.5
2016	74.2
2017	75.1
2018	76.367
2019	76.808
2020	77.253
2021	75.361
2022	77.525