Year | Value | 2021 | 26.107 | 2020 | 26.378 | 2019 | 26.839 | 2018 | 27.262 | 2017 | 27.723 | 2016 | 28.157 | 2015 | 28.305 | 2014 | 28.663 | 2013 | 29.19 | 2012 | 29.054 | 2011 | 29.093 | 2010 | 28.477 | 2009 | 28.916 | 2008 | 29.42 | 2007 | 29.699 | 2006 | 29.075 | 2005 | 28.778 | 2004 | 28.986 | 2003 | 29.611 | 2002 | 29.501 | 2001 | 29.185 | 2000 | 28.987 | 1999 | 29.351 | 1998 | 29.981 | 1997 | 30.755 | 1996 | 30.972 | 1995 | 31.098 | 1994 | 31.4 | 1993 | 32.183 | 1992 | 33.105 | 1991 | 33.815 | 1990 | 34.392 | 1989 | 35.255 | 1988 | 36.085 | 1987 | 36.677 | 1986 | 36.654 | 1985 | 36.994 | 1984 | 37.577 | 1983 | 38.089 | 1982 | 38.495 | 1981 | 39.001 | 1980 | 39.491 | 1979 | 39.991 | 1978 | 40.376 | 1977 | 40.864 | 1976 | 40.922 | 1975 | 40.728 | 1974 | 40.387 | 1973 | 40.16 | 1972 | 40.349 | 1971 | 40.639 | 1970 | 40.768 | 1969 | 41.29 | 1968 | 41.898 | 1967 | 42.544 | 1966 | 42.862 | 1965 | 43.161 | 1964 | 43.316 | 1963 | 43.742 | 1962 | 44.069 | 1961 | 44.379 | 1960 | 44.643 |
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