Year | Value | 2021 | 27.548 | 2020 | 28.038 | 2019 | 28.572 | 2018 | 29.025 | 2017 | 28.978 | 2016 | 30.527 | 2015 | 31.713 | 2014 | 31.834 | 2013 | 32.535 | 2012 | 32.885 | 2011 | 32.957 | 2010 | 33.004 | 2009 | 32.982 | 2008 | 33.206 | 2007 | 33.561 | 2006 | 34.124 | 2005 | 34.885 | 2004 | 34.535 | 2003 | 34.939 | 2002 | 35.344 | 2001 | 35.635 | 2000 | 35.865 | 1999 | 35.418 | 1998 | 35.267 | 1997 | 35.258 | 1996 | 35.415 | 1995 | 36.171 | 1994 | 36.763 | 1993 | 37.909 | 1992 | 38.744 | 1991 | 39.613 | 1990 | 40.372 | 1989 | 41.088 | 1988 | 42.043 | 1987 | 43.033 | 1986 | 43.752 | 1985 | 44.329 | 1984 | 44.922 | 1983 | 44.842 | 1982 | 44.766 | 1981 | 44.955 | 1980 | 44.838 | 1979 | 44.674 | 1978 | 44.671 | 1977 | 44.704 | 1976 | 44.962 | 1975 | 45.408 | 1974 | 45.844 | 1973 | 46.222 | 1972 | 46.526 | 1971 | 46.939 | 1970 | 47.179 | 1969 | 47.338 | 1968 | 47.199 | 1967 | 47.233 | 1966 | 47.351 | 1965 | 47.878 | 1964 | 48.361 | 1963 | 48.989 | 1962 | 49.166 | 1961 | 49.347 | 1960 | 49.804 |
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