Year | Value | 2021 | 27.254 | 2020 | 27.622 | 2019 | 27.895 | 2018 | 28.222 | 2017 | 28.579 | 2016 | 28.949 | 2015 | 29.4 | 2014 | 29.801 | 2013 | 30.155 | 2012 | 30.486 | 2011 | 30.466 | 2010 | 30.195 | 2009 | 29.781 | 2008 | 29.294 | 2007 | 28.863 | 2006 | 28.905 | 2005 | 29.118 | 2004 | 29.347 | 2003 | 29.624 | 2002 | 29.94 | 2001 | 30.478 | 2000 | 31.005 | 1999 | 31.39 | 1998 | 31.817 | 1997 | 32.161 | 1996 | 32.538 | 1995 | 32.739 | 1994 | 32.815 | 1993 | 32.646 | 1992 | 32.402 | 1991 | 32.239 | 1990 | 32.578 | 1989 | 32.917 | 1988 | 33.364 | 1987 | 33.681 | 1986 | 34.129 | 1985 | 34.205 | 1984 | 34.188 | 1983 | 34.227 | 1982 | 34.189 | 1981 | 34.309 | 1980 | 34.644 | 1979 | 35.029 | 1978 | 35.238 | 1977 | 35.478 | 1976 | 36.346 | 1975 | 37.123 | 1974 | 37.765 | 1973 | 38.391 | 1972 | 39.115 | 1971 | 39.83 | 1970 | 40.652 | 1969 | 41.277 | 1968 | 41.622 | 1967 | 42.087 | 1966 | 42.963 | 1965 | 43.791 | 1964 | 44.876 | 1963 | 45.656 | 1962 | 46.558 | 1961 | 47.322 | 1960 | 48.065 |
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