Year	years
1960	66.78
1961	67.56
1962	67.4
1963	67.11
1964	67.76
1965	67.64
1966	67.76
1967	67.93
1968	67.62
1969	67.56
1970	67.85
1971	67.88
1972	68.21
1973	68.45
1974	68.82
1975	68.82
1976	68.91
1977	69.53
1978	69.42
1979	69.94
1980	69.89
1981	70.29
1982	70.61
1983	70.63
1984	71
1985	71.13
1986	71.4
1987	72
1988	72.2
1989	72.34
1990	72.73
1991	72.88
1992	73
1993	72.96
1994	73.36
1995	73.47
1996	73.88
1997	74.2
1998	74.4
1999	74.4
2000	74.6
2001	74.9
2002	75.1
2003	75.3
2004	76
2005	76.2
2006	76.6
2007	77.1
2008	76.9
2009	77.4
2010	77.5
2011	78
2012	77.8
2013	78.1
2014	78.8
2015	78.7
2016	79
2017	79.2
2018	79.4
2019	79.8
2020	78.5
2021	79.4
2022	79.6