Year | Value | 2022 | 30.991 | 2021 | 30.906 | 2020 | 30.843 | 2019 | 30.799 | 2018 | 30.776 | 2017 | 30.773 | 2016 | 30.79 | 2015 | 30.827 | 2014 | 30.885 | 2013 | 30.964 | 2012 | 31.062 | 2011 | 31.182 | 2010 | 31.322 | 2009 | 31.463 | 2008 | 31.603 | 2007 | 31.744 | 2006 | 31.886 | 2005 | 32.028 | 2004 | 32.17 | 2003 | 32.312 | 2002 | 32.455 | 2001 | 32.598 | 2000 | 32.778 | 1999 | 32.965 | 1998 | 33.151 | 1997 | 33.339 | 1996 | 33.526 | 1995 | 33.715 | 1994 | 33.904 | 1993 | 34.093 | 1992 | 34.283 | 1991 | 34.474 | 1990 | 34.609 | 1989 | 34.735 | 1988 | 34.862 | 1987 | 34.989 | 1986 | 35.116 | 1985 | 35.243 | 1984 | 35.37 | 1983 | 35.498 | 1982 | 35.626 | 1981 | 35.754 | 1980 | 35.882 | 1979 | 35.744 | 1978 | 35.564 | 1977 | 35.385 | 1976 | 35.206 | 1975 | 35.027 | 1974 | 34.849 | 1973 | 34.672 | 1972 | 34.495 | 1971 | 34.317 | 1970 | 34.141 | 1969 | 33.567 | 1968 | 32.878 | 1967 | 32.196 | 1966 | 31.521 | 1965 | 30.855 | 1964 | 30.197 | 1963 | 29.545 | 1962 | 28.903 | 1961 | 28.269 | 1960 | 27.644 |
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