Year	years
1960	71.47
1961	69.747
1962	72.043
1963	70.305
1964	72.476
1965	72.031
1966	72.366
1967	73.235
1968	71.206
1969	71.508
1970	71.165
1971	71.685
1972	71.868
1973	72.148
1974	72.237
1975	71.651
1976	72.57
1977	72.833
1978	73.211
1979	72.509
1980	73.428
1981	73.858
1982	74.87
1983	74.041
1984	76.076
1985	75.266
1986	75.616
1987	76.623
1988	77.045
1989	77.211
1990	77.185
1991	76.617
1992	78.125
1993	76.547
1994	78.005
1995	77.749
1996	77.962
1997	78.211
1998	78.898
1999	78.935
2000	79.155
2001	79.277
2002	78.906
2003	79.618
2004	80.125
2005	80.344
2006	80.694
2007	81.166
2008	81.317
2009	80.995
2010	81.12
2011	81.726
2012	81.339
2013	81.516
2014	81.884
2015	81.433
2016	81.366
2017	81.331
2018	81.375
2019	81.39
2020	81.264
2021	81.232
2022	81.583