Year years 1960 43.608 1961 43.467 1962 42.569 1963 43.476 1964 43.357 1965 43.279 1966 43.042 1967 43.043 1968 43.075 1969 43.235 1970 43.625 1971 44.156 1972 44.885 1973 45.6 1974 46.74 1975 47.693 1976 48.781 1977 50.136 1978 51.386 1979 52.923 1980 54.629 1981 56.81 1982 59.171 1983 61.288 1984 63.268 1985 65.195 1986 66.913 1987 67.239 1988 67.901 1989 68.102 1990 68.517 1991 69.007 1992 69.307 1993 69.202 1994 69.169 1995 69.518 1996 70.4 1997 70.925 1998 71.262 1999 71.414 2000 71.949 2001 72.197 2002 72.559 2003 72.25 2004 72.812 2005 73.075 2006 73.379 2007 73.735 2008 74.071 2009 74.864 2010 74.873 2011 75.236 2012 75.478 2013 75.84 2014 76.467 2015 76.824 2016 76.803 2017 76.821 2018 77.205 2019 77.76 2020 75.912 2021 77.959 2022 78.457