Year years 1960 50.139 1961 50.902 1962 51.635 1963 52.294 1964 52.832 1965 53.114 1966 53.382 1967 53.47 1968 53.559 1969 53.777 1970 54.276 1971 55.025 1972 55.888 1973 56.798 1974 57.604 1975 58.251 1976 58.743 1977 59.142 1978 59.505 1979 59.661 1980 56.774 1981 60.278 1982 60.229 1983 61.918 1984 62.886 1985 63.854 1986 64.175 1987 65.725 1988 66.701 1989 67.271 1990 68.309 1991 69.066 1992 69.713 1993 70.308 1994 70.889 1995 71.283 1996 71.893 1997 72.559 1998 72.929 1999 73.803 2000 74.248 2001 73.903 2002 74.708 2003 74.682 2004 74.968 2005 75.083 2006 75.401 2007 75.677 2008 75.92 2009 75.961 2010 76.213 2011 76.189 2012 76.163 2013 76.158 2014 76.267 2015 76.572 2016 77.075 2017 77.494 2018 77.488 2019 76.776 2020 75.413 2021 75.149 2022 75.813