Year years 1960 69.30000000000001 1961 70.31585365853658 1962 70.2549756097561 1963 70.61053658536586 1964 70.56939024390246 1965 71.42831707317073 1966 71.75270731707317 1967 71.29878048780489 1968 71.43019512195121 1969 72.00434146341465 1970 72.77080487804878 1971 73.00956097560976 1972 72.78268292682927 1973 72.9819756097561 1974 73.41558536585367 1975 73.37636585365856 1976 73.63400000000001 1977 73.67080487804878 1978 74.35875609756098 1979 74.62107317073172 1980 74.54626829268294 1981 74.95743902439024 1982 75.25053658536586 1983 75.51773170731708 1984 75.77439024390245 1985 76.08290243902441 1986 76.48265853658536 1987 76.27985365853658 1988 76.98075609756097 1989 76.6878048780488 1990 76.93902439024392 1991 77.13658536585366 1992 77.3829268292683 1993 77.39024390243904 1994 77.63902439024392 1995 77.58536585365854 1996 77.68536585365854 1997 78.13658536585366 1998 77.83902439024392 1999 77.98780487804879 2000 77.8878048780488 2001 78.38780487804878 2002 78.64146341463415 2003 78.84146341463415 2004 79.0390243902439 2005 79.23902439024391 2006 79.43902439024392 2007 79.43902439024392 2008 79.93902439024392 2009 80.18780487804878 2010 80.3878048780488 2011 80.73170731707317 2012 80.63414634146342 2013 81.28536585365853 2014 81.38536585365853 2015 81.03658536585367 2016 81.3878048780488 2017 81.28780487804877 2018 81.7878048780488 2019 81.63902439024392 2020 81.28780487804877 2021 80.0829268292683 2022 80.63658536585366