Year	years
1960	66.68
1961	67.1
1962	67.08
1963	67.13
1964	67.79
1965	68.18
1966	68.46
1967	68.57
1968	68.85
1969	68.36
1970	69.32
1971	68.84
1972	70.14
1973	69.84
1974	70.16
1975	70.47
1976	70.75
1977	71.21
1978	71.32
1979	71.77
1980	72.32
1981	72.47
1982	73.1
1983	72.87
1984	73.11
1985	73.04
1986	73.33
1987	73.45
1988	73.43
1989	73.36
1990	73.34
1991	73.42
1992	73.81
1993	74.01
1994	74.36
1995	74.41
1996	74.54
1997	75.17
1998	75.3
1999	75.4
2000	75.6
2001	76.1
2002	76.3
2003	76.4
2004	76.7
2005	77
2006	77.7
2007	77.8
2008	78.2
2009	78.5
2010	78.7
2011	79.5
2012	79.5
2013	80.2
2014	80.4
2015	80.1
2016	80.5
2017	80.6
2018	80.7
2019	81.1
2020	79.6
2021	80.4
2022	80.4