Year years 1960 69.77073170731707 1961 70.27073170731708 1962 70.11951219512196 1963 69.91707317073171 1964 70.16585365853659 1965 70.21463414634147 1966 70.21219512195123 1967 70.56097560975611 1968 69.95121951219512 1969 70.50731707317075 1970 70.80731707317074 1971 71.10731707317075 1972 71.15609756097562 1973 71.35609756097561 1974 71.9560975609756 1975 72.60487804878048 1976 72.85609756097561 1977 73.25609756097562 1978 73.35609756097561 1979 73.8048780487805 1980 73.60975609756099 1981 74.009756097561 1982 74.3609756097561 1983 74.46341463414633 1984 74.56341463414635 1985 74.56341463414635 1986 74.61463414634147 1987 74.7658536585366 1988 74.7658536585366 1989 75.01707317073172 1990 75.21463414634147 1991 75.3658536585366 1992 75.6170731707317 1993 75.41951219512197 1994 75.61951219512196 1995 75.6219512195122 1996 76.02682926829269 1997 76.42926829268293 1998 76.58048780487806 1999 76.5829268292683 2000 76.63658536585366 2001 76.83658536585367 2002 76.93658536585366 2003 77.03658536585367 2004 77.48780487804878 2005 77.48780487804878 2006 77.68780487804878 2007 77.98780487804879 2008 78.03902439024391 2009 78.39024390243902 2010 78.54146341463415 2011 78.64146341463415 2012 78.74146341463415 2013 78.74146341463415 2014 78.84146341463415 2015 78.69024390243904 2016 78.53902439024391 2017 78.53902439024391 2018 78.63902439024392 2019 78.78780487804877 2020 76.98048780487805 2021 76.32926829268293 2022 77.43414634146343