Year years 1960 69.03760636121159 1961 69.43735429967667 1962 69.28127311203902 1963 69.64127047045216 1964 70.16091885718484 1965 70.27086513001301 1966 70.58235186087644 1967 70.58984419758461 1968 70.59593239055057 1969 70.42180243219781 1970 70.82235693055478 1971 70.96579800574396 1972 71.35053997894074 1973 71.46880376601514 1974 71.77990296055562 1975 71.79896674272506 1976 72.06914828579566 1977 72.3941776016688 1978 72.48511017675658 1979 72.76698494423339 1980 72.78960621699404 1981 73.125229633857 1982 73.40334558310505 1983 73.44889921351474 1984 73.74048172064761 1985 73.81547330955259 1986 74.07156470331138 1987 74.32453372535159 1988 74.52677694412273 1989 74.65464948234744 1990 74.69732687513049 1991 74.8099607606176 1992 75.12689288181278 1993 75.25540133964091 1994 75.52573652228679 1995 75.67124375556426 1996 75.92402182997611 1997 76.24187546867188 1998 76.51124162501134 1999 76.74520018887368 2000 77.07531688406453 2001 77.42295017489741 2002 77.53100329864203 2003 77.5893359969316 2004 78.11449989571591 2005 78.27142866781237 2006 78.668010036854 2007 78.9018190892451 2008 79.12529640987692 2009 79.35763602321676 2010 79.63003371246744 2011 80.13874214924849 2012 80.15765948612611 2013 80.46479376896012 2014 80.87198239658558 2015 80.5684394242096 2016 80.95129748073016 2017 80.92820864686587 2018 81.02872899908027 2019 81.31485796394043 2020 80.4508691329259 2021 80.31661322597562 2022 80.80262110738526