Year years 1960 43.47608433744033 1961 48.59157458492817 1962 55.583016049885714 1963 56.135944556973776 1964 56.845611093208255 1965 57.05642207924823 1966 57.92026821905633 1967 58.71990679785229 1968 59.15637137234999 1969 59.774943200669874 1970 60.39499305097985 1971 61.170200689891544 1972 61.75451832361476 1973 62.60871915148481 1974 63.291541730438006 1975 63.976661180698024 1976 64.71725789257411 1977 65.47565080159323 1978 66.11924478062826 1979 66.71645075454613 1980 67.2100660486132 1981 67.68708780256058 1982 68.16987274506104 1983 68.58272568964291 1984 68.96521013322952 1985 69.33592866740075 1986 69.72240339585726 1987 70.0753184326756 1988 70.34079807690765 1989 70.66607842939992 1990 70.8389984012166 1991 70.902076227998 1992 71.42248214749608 1993 71.97574786794897 1994 72.15988429570781 1995 72.46476472233327 1996 72.71735845317833 1997 73.08946861668322 1998 73.57095955992463 1999 73.62955718881577 2000 74.07158521851213 2001 74.85866411650383 2002 75.16964129098103 2003 75.64042590454095 2004 75.68531690612919 2005 76.20133436472958 2006 76.5488235595134 2007 76.81324164209038 2008 76.71940512225758 2009 77.33094976641095 2010 77.50969073468153 2011 77.74772391862903 2012 78.03521449205736 2013 78.29890539221525 2014 78.53986663945689 2015 78.76569372590158 2016 78.98899679178095 2017 79.19706779145719 2018 79.48332142154678 2019 79.65921276034409 2020 79.70019893525942 2021 79.32843292592746 2022 79.71401487261012