Year years 1960 67.865 1961 67.704 1962 68.387 1963 69.384 1964 69.495 1965 68.489 1966 69.541 1967 70.031 1968 70.002 1969 70.733 1970 71.569 1971 71.453 1972 71.631 1973 71.82 1974 71.961 1975 72.118 1976 72.226 1977 72.235 1978 72.302 1979 72.387 1980 72.487 1981 72.665 1982 73.018 1983 72.624 1984 72.795 1985 72.617 1986 73.449 1987 73.581 1988 74.226 1989 74.233 1990 74.463 1991 75.917 1992 75.327 1993 75.483 1994 75.654 1995 75.821 1996 75.98 1997 76.154 1998 76.326 1999 76.502 2000 76.663 2001 76.847 2002 77.031 2003 77.206 2004 77.384 2005 77.555 2006 77.726 2007 77.892 2008 78.068 2009 78.236 2010 78.406 2011 78.827 2012 79.022 2013 78.908 2014 79.966 2015 79.309 2016 79.475 2017 78.59 2018 80.614 2019 79.983 2020 80.149 2021 80.379 2022 80.55