Year years 1960 55.125 1961 56.693 1962 56.377 1963 55.653 1964 57.783 1965 58.739 1966 60.734 1967 60.782 1968 61.495 1969 61.509 1970 62.155 1971 62.942 1972 63.895 1973 64.261 1974 64.892 1975 65.319 1976 65.968 1977 66.561 1978 67.605 1979 67.759 1980 67.232 1981 67.77 1982 68.098 1983 67.47 1984 67.912 1985 67.885 1986 68.503 1987 68.521 1988 68.937 1989 69.09 1990 68.826 1991 69.522 1992 68.847 1993 69.457 1994 69.4 1995 69.8 1996 70.3 1997 70.3 1998 70.2 1999 70.4 2000 70.8 2001 70.9 2002 70.6 2003 70.9 2004 71.5 2005 71.6 2006 71.7 2007 71.8 2008 72.4 2009 72.3 2010 72.9 2011 73.1 2012 73 2013 73.4 2014 73.5 2015 73.5 2016 73.4 2017 74.1 2018 74.6 2019 74.7 2020 72.2 2021 71.1 2022 72.22