Year	years
1960	73.49
1961	73.92
1962	73.19
1963	73.65
1964	74.89
1965	74.86
1966	74.6
1967	74.22
1968	74.54
1969	74.55
1970	74.23
1971	74.8
1972	74.76
1973	74.5
1974	74.74
1975	74.16
1976	74.39
1977	74.16
1978	74.12
1979	73.72
1980	74.12
1981	74.4
1982	74.65
1983	74.62
1984	74.5
1985	74.06
1986	75.14
1987	75.19
1988	75.22
1989	75.18
1990	74.6
1991	74.6
1992	74.44
1993	73.33
1994	72.62
1995	73.06
1996	74.8
1997	75.05
1998	74.8
1999	75.29
2000	76
2001	76.6
2002	76.8
2003	76.9
2004	77.2
2005	77.4
2006	76.5
2007	76.5
2008	77.9
2009	78.1
2010	78.4
2011	78.8
2012	78.9
2013	78.9
2014	79.4
2015	79.5
2016	79.6
2017	79.7
2018	79.7
2019	80.1
2020	80
2021	78
2022	79.6