Year years 1960 52.264 1961 53.268 1962 54.215 1963 55.044 1964 56.027 1965 56.845 1966 57.253 1967 58.41 1968 59.119 1969 59.743 1970 58.731 1971 60.831 1972 61.556 1973 62.072 1974 62.543 1975 63.065 1976 63.549 1977 63.993 1978 64.404 1979 64.775 1980 65.169 1981 65.601 1982 66.002 1983 66.358 1984 66.699 1985 67.004 1986 67.291 1987 67.579 1988 67.902 1989 68.19 1990 68.46 1991 68.679 1992 68.899 1993 69.098 1994 69.274 1995 69.446 1996 69.613 1997 69.766 1998 69.919 1999 70.109 2000 70.313 2001 70.528 2002 70.724 2003 70.928 2004 71.117 2005 71.264 2006 71.48 2007 71.654 2008 71.818 2009 71.972 2010 72.117 2011 72.26 2012 72.399 2013 72.565 2014 72.796 2015 73.03 2016 73.222 2017 73.46 2018 73.677 2019 73.894 2020 72.987 2021 72.128 2022 72.12