Year years 1960 57.84140879267924 1961 58.165893875836396 1962 58.337644171470416 1963 58.720488329092895 1964 59.115815967076585 1965 59.25113192182403 1966 59.41756428436184 1967 59.48308442476146 1968 59.613275646210894 1969 59.59022184708232 1970 59.723856943435905 1971 60.055910781576436 1972 60.28149503009076 1973 60.533920136401434 1974 60.65570808259838 1975 60.771349813908664 1976 60.96123909481844 1977 61.025814853107114 1978 61.1781534396227 1979 61.23363594841223 1980 61.78563046450588 1981 62.05691408810091 1982 62.36441186290256 1983 62.582817455860685 1984 62.7260034162246 1985 63.154615519060236 1986 63.93757446890394 1987 64.26825372603305 1988 64.27461763357607 1989 64.53821050632963 1990 64.50998793536492 1991 64.19898195006068 1992 63.1520865650446 1993 62.78043934008921 1994 63.20025644770532 1995 63.088346910205416 1996 63.476608713532165 1997 63.90292185882228 1998 64.43490593082113 1999 64.45814293852045 2000 64.97032273840973 2001 65.296934931846 2002 65.63194400126076 2003 65.87727784278829 2004 66.13588497180179 2005 66.2091631550023 2006 66.55003190952503 2007 66.86405851090673 2008 67.21140265678865 2009 67.76999964302004 2010 68.26949687731216 2011 68.48944198190647 2012 68.98222092362646 2013 69.38922116339772 2014 69.62475141037407 2015 69.81903997769062 2016 70.03296145911835 2017 70.431248778111 2018 70.63093882240246 2019 70.87801103429105 2020 69.21171279801217 2021 69.26908665008771 2022 70.72011291493992