Year	years
1961	73.62
1962	73.7
1966	73.73
1967	73.2
1968	72.88
1969	72.84
1970	72.96
1971	73.44
1972	72
1973	73.23
1974	73.27
1975	73.93
1976	74.8
1977	74.7
1978	75
1979	75.3
1980	75.74
1981	75.9
1982	75.8
1983	76.2
1984	76.6
1985	77
1986	76.8
1987	77
1988	75
1989	78.1
1990	78.4
1991	78.5
1992	78.4
1993	79.1
1994	79.4
1995	79.5
1996	80
1997	80.1
1998	80.3
1999	80.4
2000	80.9
2001	81.2
2002	81.5
2003	81.8
2004	82.4
2005	82.2
2006	82.5
2007	82.4
2008	83
2009	83.3
2010	83.6
2011	83.5
2012	83.6
2013	83.9
2014	84.1
2015	84.1
2016	84.2
2017	84.6
2018	84.8
2019	84.7
2020	84.8
2021	84.6
2022	84.8