Year years 1960 61.29247438143699 1961 61.653803770866006 1962 62.643921754256276 1963 63.13687862932555 1964 63.886801916729475 1965 64.26644621099493 1966 64.59766946998832 1967 64.95332458615194 1968 65.2033065514657 1969 65.46546161839076 1970 65.76987468018208 1971 65.84572148844546 1972 66.13988235843614 1973 66.34403842248 1974 66.63726148468602 1975 66.95370386786911 1976 67.20128143430411 1977 67.38793890948087 1978 67.59618386347029 1979 67.74269328158185 1980 67.97107457432767 1981 68.198540485263 1982 68.36001172998114 1983 68.60671691400128 1984 68.90188869442524 1985 69.03567823661362 1986 69.31719683173695 1987 69.4116679791286 1988 69.64148301027363 1989 69.78716922982717 1990 69.95035497533543 1991 70.13709946734429 1992 70.41503122899964 1993 70.65959669520423 1994 70.84628861140851 1995 70.84197863963628 1996 70.99560735770078 1997 71.02452926287947 1998 71.20132830715114 1999 71.32853901422781 2000 71.5804362668297 2001 71.78300315898953 2002 71.93226062610373 2003 71.96348163067563 2004 72.30819459380915 2005 72.67845868795195 2006 73.12281069594462 2007 73.5087467186131 2008 73.79346075522831 2009 74.1205733726894 2010 74.3207523149655 2011 74.39197200528987 2012 74.50920622405194 2013 74.59599095349525 2014 74.80360672890173 2015 75.05902452172631 2016 75.4175370081085 2017 75.6575848373518 2018 75.9749610277166 2019 75.51816962583409 2020 75.68568700199377 2021 73.75736069924847 2022 74.30510665014425