Year years 1960 43.8163517628787 1961 44.34191986387283 1962 44.82638979586874 1963 45.18528722446418 1964 45.883454881041565 1965 46.07704967282792 1966 46.54663977437211 1967 47.108378298916236 1968 47.624829810966425 1969 47.985594546766 1970 47.44661259821745 1971 46.49626345748658 1972 48.99498362549128 1973 49.52221012642194 1974 49.592758388811376 1975 49.73069383767137 1976 50.31541217065768 1977 51.01444087712619 1978 51.52327626461199 1979 52.00965181683987 1980 52.47949588388435 1981 52.90178479642048 1982 53.20777198125393 1983 52.988440084826095 1984 53.25837914966352 1985 53.447235379512435 1986 53.838425388550874 1987 54.26360306893067 1988 54.2701210207091 1989 54.81192341262688 1990 55.071944979887576 1991 54.78132760659598 1992 55.12329514989963 1993 55.332049134147326 1994 55.59399732219755 1995 55.835113716083576 1996 55.94917897949036 1997 56.491625430279576 1998 56.810371653885 1999 57.681606176452256 2000 57.99949536848394 2001 58.38859612894696 2002 58.84451553170929 2003 59.33878162152614 2004 59.65668008014208 2005 60.15382936605125 2006 60.84997381915246 2007 61.2715798085772 2008 61.45041287526241 2009 62.20763866778255 2010 62.662982792470316 2011 63.28787857249645 2012 63.722385087828876 2013 64.2056258410915 2014 64.48140579228406 2015 64.82840424178272 2016 65.23848709330623 2017 65.65950635469851 2018 65.9828942826466 2019 66.34290527402939 2020 65.92411790269199 2021 65.61177218199411 2022 66.29753388015855