Year	Years
1950	68.52
1951	68.71
1952	69.09
1953	69.43
1954	69.72
1955	69.97
1956	70.19
1957	70.37
1958	70.52
1959	70.64
1960	70.74
1961	70.83
1962	70.93
1963	71.03
1964	71.14
1965	71.27
1966	71.39
1967	71.51
1968	71.62
1969	71.73
1970	71.82
1971	71.92
1972	72.02
1973	72.13
1974	72.26
1975	72.41
1976	72.58
1977	72.77
1978	72.98
1979	73.21
1980	73.44
1981	73.67
1982	73.89
1983	74.1
1984	74.3
1985	74.49
1986	74.68
1987	74.87
1988	75.07
1989	75.29
1990	75.51
1991	75.73
1992	75.94
1993	76.14
1994	76.34
1995	76.53
1996	76.72
1997	76.92
1998	77.14
1999	77.37
2000	77.61
2001	77.87
2002	78.14
2003	78.41
2004	78.67
2005	78.93
2006	79.16
2007	79.38
2008	79.57
2009	79.75
2010	79.9
2011	80.05
2012	80.19
2013	80.32
2014	80.47
2015	80.61
2016	80.76
2017	80.91
2018	81.06