Year years 1960 54.05 1961 54.496 1962 54.999 1963 55.56 1964 56.157 1965 56.827 1966 57.598 1967 58.409 1968 59.175 1969 59.926 1970 60.571 1971 61.176 1972 61.807 1973 62.386 1974 62.962 1975 63.526 1976 64.143 1977 64.655 1978 65.187 1979 65.672 1980 66.158 1981 66.658 1982 67.167 1983 67.677 1984 68.19 1985 68.681 1986 69.147 1987 69.442 1988 69.803 1989 70.039 1990 70.21 1991 70.313 1992 70.824 1993 71.871 1994 70.718 1995 60.894 1996 60.956 1997 60.974 1998 60.906 1999 60.798 2000 60.763 2001 60.745 2002 60.792 2003 69.546 2004 69.437 2005 69.285 2006 69.085 2007 68.911 2008 68.958 2009 69.732 2010 70.419 2011 70.978 2012 71.626 2013 72.319 2014 72.942 2015 72.784 2016 72.805 2017 72.978 2018 73.031 2019 73.198 2020 73.274 2021 73.284 2022 73.578