Year years 1960 64.69468292682927 1961 65.5179512195122 1962 66.28575609756098 1963 66.71470731707318 1964 67.07439024390244 1965 67.51251219512196 1966 67.79700000000001 1967 68.11931707317073 1968 68.28826829268293 1969 68.68626829268293 1970 68.91312195121951 1971 69.18834146341464 1972 69.34678048780489 1973 69.73980487804879 1974 70.20134146341464 1975 70.78343902439025 1976 71.1650731707317 1977 71.37112195121954 1978 71.546756097561 1979 71.63921951219513 1980 72.19024390243904 1981 72.58780487804879 1982 72.68780487804878 1983 73.03658536585368 1984 73.29024390243903 1985 73.89024390243904 1986 74.24634146341464 1987 74.54878048780488 1988 74.69756097560976 1989 74.94634146341464 1990 75.29512195121951 1991 75.64634146341463 1992 75.94634146341464 1993 76.04634146341465 1994 76.19756097560976 1995 76.2951219512195 1996 76.59512195121953 1997 76.89756097560975 1998 77.30000000000001 1999 77.55121951219512 2000 77.95121951219514 2001 78.25121951219512 2002 78.55121951219512 2003 79.0390243902439 2004 79.49024390243902 2005 79.99024390243903 2006 80.14146341463415 2007 80.44146341463416 2008 80.79024390243903 2009 81.24146341463415 2010 81.54146341463417 2011 81.7439024390244 2012 81.99512195121952 2013 82.24634146341465 2014 82.49512195121953 2015 82.7439024390244 2016 82.84634146341465 2017 83.09512195121954 2018 83.29756097560976 2019 83.59512195121953 2020 83.5439024390244 2021 83.09268292682928 2022 82.89512195121952