Year years 1960 61.354854722431575 1961 61.54790424785897 1962 61.38645373691028 1963 61.93764720426801 1964 62.43166111462217 1965 62.32178709407434 1966 62.408654898757185 1967 62.12811584941189 1968 62.14572526680483 1969 61.732837142948235 1970 62.221443490761985 1971 62.423195143550785 1972 62.63679286559563 1973 62.790328118039014 1974 62.869865836594116 1975 62.614648117692745 1976 62.607548767494926 1977 62.4536645649369 1978 62.49799060507821 1979 62.408255072346265 1980 62.5326985246197 1981 62.86164779962884 1982 63.225821875726155 1983 63.282553917558076 1984 63.164092553948514 1985 63.68364159056519 1986 64.78253090729774 1987 64.9407560340108 1988 64.91926566845207 1989 64.8785750262494 1990 64.66566743622074 1991 64.38019533699969 1992 63.40567861613665 1993 62.24132692159325 1994 61.973848343624184 1995 62.1130641731813 1996 62.83379677463317 1997 63.479411262276635 1998 63.96356705651208 1999 63.582034052099786 2000 63.68943226312517 2001 63.886243654525074 2002 63.99443458691338 2003 64.1099957068908 2004 64.42680702019122 2005 64.50433316079017 2006 65.20325212957603 2007 65.7287431661158 2008 66.08961465774584 2009 66.73687149098534 2010 67.13554668195196 2011 67.64612764497787 2012 68.0860342686139 2013 68.55422064204791 2014 68.77552216380384 2015 69.06008244779183 2016 69.40324728784175 2017 69.93026760507658 2018 70.10193608426171 2019 70.43506113815172 2020 68.76674438084609 2021 68.33731475153094 2022 70.05220177452053