Year years 1960 55.083024390243914 1961 55.3209512195122 1962 55.648926829268305 1963 55.976951219512195 1964 56.18034146341464 1965 56.40948780487806 1966 56.81014634146342 1967 57.03431707317073 1968 57.35746341463415 1969 57.671536585365864 1970 58.00531707317074 1971 58.3039268292683 1972 58.61475609756098 1973 58.99068292682928 1974 59.327048780487814 1975 59.461756097560986 1976 59.66558536585366 1977 60.03975609756098 1978 60.375609756097575 1979 60.79502439024392 1980 61.08146341463415 1981 61.349195121951226 1982 61.67443902439025 1983 62.17707317073171 1984 62.42119512195123 1985 63.019512195121955 1986 63.330414634146344 1987 63.66043902439024 1988 63.917390243902446 1989 67.90731707317074 1990 68.29756097560976 1991 68.55121951219513 1992 68.10243902439025 1993 67.19268292682928 1994 66.03902439024391 1995 65.79024390243903 1996 66.54390243902441 1997 66.89268292682927 1998 67.05121951219513 1999 68.65609756097562 2000 68.55853658536587 2001 68.70731707317073 2002 68.15609756097561 2003 68.25609756097562 2004 68.15365853658537 2005 67.95609756097562 2006 67.6951219512195 2007 67.89512195121952 2008 68.45121951219512 2009 69.10243902439026 2010 69.30000000000001 2011 69.60243902439025 2012 70.00243902439024 2013 70.20243902439024 2014 70.40243902439025 2015 70.65121951219513 2016 70.95121951219512 2017 71.20000000000002 2018 71.4 2019 71.60000000000001 2020 71.80000000000001 2021 71.9 2022 72.04878048780488