Year years 1960 67.46521951219512 1961 67.6309512195122 1962 67.30051219512195 1963 67.75717073170732 1964 68.36717073170733 1965 67.88775609756097 1966 67.90119512195123 1967 67.59380487804879 1968 67.48936585365855 1969 66.87629268292685 1970 68.13365853658536 1971 68.37658536585366 1972 68.30853658536587 1973 68.29463414634148 1974 68.32024390243903 1975 67.7239024390244 1976 67.48756097560975 1977 67.37634146341463 1978 67.3909756097561 1979 67.11439024390243 1980 67.0339024390244 1981 67.26390243902439 1982 67.80609756097562 1983 67.65268292682927 1984 67.20268292682927 1985 67.85682926829269 1986 69.38975609756099 1987 69.44000000000001 1988 69.46439024390244 1989 69.17170731707317 1990 68.88609756097561 1991 68.47439024390245 1992 66.87317073170732 1993 64.9358536585366 1994 64.46707317073171 1995 64.69073170731708 1996 65.85414634146342 1997 66.6987804878049 1998 67.02975609756098 1999 65.98219512195124 2000 65.48365853658537 2001 65.38341463414635 2002 65.12878048780489 2003 65.02756097560976 2004 65.4709756097561 2005 65.52975609756099 2006 66.72756097560976 2007 67.58682926829269 2008 67.94926829268293 2009 68.68463414634147 2010 68.84121951219514 2011 69.6839024390244 2012 70.07219512195124 2013 70.57878048780488 2014 70.74365853658537 2015 71.18341463414635 2016 71.65121951219513 2017 72.45146341463416 2018 72.66219512195121 2019 73.0839024390244 2020 71.3387804878049 2021 69.90024390243903 2022 72.54560975609758