Year	years
1960	68.65
1961	68.84
1962	68.44
1963	68.29
1964	69.19
1965	69.47
1966	69.56
1967	69.7
1968	69.8
1969	69.72
1970	70.03
1971	70.16
1972	70.62
1973	70.98
1974	71.17
1975	71.49
1976	71.6
1977	71.96
1978	71.88
1979	72.31
1980	72.23
1981	72.42
1982	72.79
1983	72.68
1984	73.35
1985	73.48
1986	73.66
1987	73.9
1988	73.89
1989	74.07
1990	73.94
1991	74.1
1992	74.45
1993	74.9
1994	75.15
1995	75.3
1996	75.94
1997	76.26
1998	76.3
1999	76.8
2000	76.9
2001	77.4
2002	77.8
2003	78
2004	78.6
2005	78.7
2006	79.1
2007	79.4
2008	79.7
2009	79.8
2010	80.1
2011	80.5
2012	80.6
2013	80.7
2014	81.1
2015	80.8
2016	81.7
2017	81.6
2018	81.9
2019	82.1
2020	81
2021	81.8
2022	81.6