Year years 1960 69.70195121951221 1961 70.52097560975609 1962 70.21951219512196 1963 70.05146341463416 1964 70.75512195121952 1965 70.62536585365855 1966 70.70634146341465 1967 71.01292682926831 1968 70.69317073170733 1969 70.76487804878049 1970 70.9719512195122 1971 71.06048780487806 1972 71.40512195121951 1973 71.63536585365856 1974 71.98585365853658 1975 71.97121951219512 1976 72.119756097561 1977 72.77390243902441 1978 72.69804878048781 1979 73.19365853658537 1980 73.20707317073172 1981 73.62170731707319 1982 73.88804878048782 1983 73.86902439024391 1984 74.40487804878049 1985 74.52024390243903 1986 74.73170731707319 1987 75.3658536585366 1988 75.5658536585366 1989 75.63268292682929 1990 76.0519512195122 1991 76.19219512195123 1992 76.35121951219513 1993 76.34536585365854 1994 76.69170731707318 1995 76.84073170731709 1996 77.18731707317073 1997 77.37073170731709 1998 77.47317073170733 1999 77.61951219512196 2000 77.72195121951219 2001 77.97317073170734 2002 78.07560975609758 2003 78.12926829268292 2004 78.8780487804878 2005 78.98048780487807 2006 79.38048780487804 2007 79.7829268292683 2008 79.68048780487806 2009 80.03414634146341 2010 80.1829268292683 2011 80.58536585365854 2012 80.38536585365854 2013 80.58780487804879 2014 81.28780487804877 2015 80.99268292682929 2016 81.4390243902439 2017 81.49268292682927 2018 81.59512195121953 2019 81.99512195121952 2020 80.69512195121952 2021 81.79024390243904 2022 81.69756097560978