Year years 1960 68.97804878048781 1961 68.97804878048781 1962 68.97804878048781 1963 68.62195121951221 1964 68.66341463414635 1965 68.3658536585366 1966 69.01219512195124 1967 69.36585365853658 1968 68.91707317073171 1969 68.3609756097561 1970 68.60975609756099 1971 68.83414634146342 1972 69.05853658536587 1973 69.40487804878049 1974 70.1609756097561 1975 70.35853658536587 1976 70.30731707317074 1977 70.55609756097562 1978 70.70243902439024 1979 70.85365853658537 1980 71.10487804878049 1981 71.2048780487805 1982 71.05365853658537 1983 70.54146341463417 1984 70.90243902439026 1985 71.35121951219513 1986 71.80243902439027 1987 72.00243902439024 1988 72.44634146341464 1989 72.7048780487805 1990 73.20487804878049 1991 73.35365853658537 1992 73.3048780487805 1993 73.25365853658538 1994 73.4048780487805 1995 73.95853658536586 1996 74.45853658536585 1997 74.70731707317073 1998 74.80731707317075 1999 75.00975609756098 2000 75.41219512195123 2001 75.75853658536586 2002 76.00731707317074 2003 76.85853658536585 2004 77.20731707317073 2005 77.61219512195122 2006 78.08658536585367 2007 78.56097560975611 2008 78.7658536585366 2009 78.97073170731707 2010 79.4219512195122 2011 79.97073170731709 2012 80.12439024390244 2013 80.3219512195122 2014 81.0780487804878 2015 80.77560975609757 2016 81.17560975609757 2017 81.02926829268294 2018 81.3780487804878 2019 81.52926829268293 2020 80.53170731707318 2021 80.67560975609756 2022 81.28292682926829