Year years 1960 70.264 1961 70.848 1962 71.17 1963 72.044 1964 72.747 1965 73.337 1966 73.618 1967 73.792 1968 74.206 1969 74.451 1970 75.105 1971 75.33 1972 75.4 1973 75.86 1974 76.26 1975 76.84 1976 76.19 1977 76.74 1978 76.66 1979 76.89 1980 77.87 1981 78.54 1982 78.44 1983 78.38 1984 78.97 1985 79.19 1986 79.44 1987 79.72 1988 79.88 1989 80.02 1990 80.28 1991 80.69 1992 80.68 1993 80.91 1994 81.54 1995 81.46 1996 82.67 1997 83.17 1998 82.97 1999 83.2 2000 83.89 2001 84.6 2002 84.51 2003 84.35 2004 84.77 2005 84.59 2006 85.54 2007 85.44 2008 85.47 2009 85.92 2010 86 2011 86.69 2012 86.38 2013 86.72 2014 86.85 2015 87.29 2016 87.3 2017 87.61 2018 87.61 2019 88.06 2020 87.75 2021 87.94 2022 86.77