Year	years
1960	71.34
1961	71.17
1962	70.97
1963	70.78
1964	71.23
1965	71.05
1966	71.41
1967	71.33
1968	71.22
1969	70.8
1970	71.01
1971	71.15
1972	71.33
1973	71.33
1974	71.7
1975	71.72
1976	72.02
1977	72.26
1978	72.36
1979	72.17
1980	72.34
1981	72.63
1982	72.65
1983	72.74
1984	73
1985	72.59
1986	72.89
1987	72.75
1988	73.04
1989	73.32
1990	73.43
1991	74.01
1992	74.16
1993	74.22
1994	74.88
1995	74.8
1996	75.37
1997	75.45
1998	75.5
1999	75.6
2000	76
2001	76.2
2002	76.5
2003	77
2004	77.5
2005	77.7
2006	78.1
2007	78.2
2008	78.3
2009	78.6
2010	78.9
2011	79.1
2012	79.5
2013	79.8
2014	80.1
2015	80.5
2016	80.7
2017	81
2018	81.1
2019	81.3
2020	81.6
2021	81.7
2022	81