Year years 1960 41.96 1961 41.743 1962 41.747 1963 42.061 1964 41.863 1965 42.45 1966 43.121 1967 43.498 1968 43.785 1969 44.116 1970 44.419 1971 44.725 1972 44.984 1973 45.19 1974 45.509 1975 45.513 1976 45.627 1977 45.765 1978 45.584 1979 46.167 1980 46.299 1981 46.555 1982 46.776 1983 46.955 1984 47.287 1985 47.389 1986 47.783 1987 48.112 1988 48.843 1989 49.224 1990 49.85 1991 50.181 1992 50.652 1993 51.27 1994 51.554 1995 52.333 1996 51.621 1997 52.626 1998 53.144 1999 53.388 2000 53.81 2001 54.055 2002 54.312 2003 54.597 2004 54.985 2005 55.454 2006 56.081 2007 56.352 2008 56.818 2009 57.463 2010 57.999 2011 58.658 2012 58.81 2013 59.439 2014 60.013 2015 60.254 2016 60.904 2017 61.107 2018 61.767 2019 62.243 2020 61.7 2021 61.521 2022 62.05