Year | Value | 2021 | 24.737844485801 | 2020 | 24.735283114887 | 2019 | 24.895455358085 | 2018 | 24.764432716918 | 2017 | 24.897894386024 | 2016 | 24.897871776527 | 2015 | 24.99419630793 | 2014 | 25.059999363198 | 2013 | 25.09189291013 | 2012 | 25.288146720087 | 2011 | 25.241281752297 | 2010 | 25.29629970884 | 2009 | 25.549699792009 | 2008 | 25.606671368556 | 2007 | 25.434762428683 | 2006 | 25.808931601903 | 2005 | 25.994839144694 | 2004 | 26.109308475527 | 2003 | 26.205181584221 | 2002 | 26.426243897529 | 2001 | 26.777424428047 | 2000 | 27.405663600298 | 1999 | 27.63487500242 | 1998 | 27.670478996549 | 1997 | 27.958216904699 | 1996 | 27.985444102439 | 1995 | 27.923262129995 | 1994 | 28.308837456657 | 1993 | 28.505577143023 | 1992 | 28.258209414588 | 1991 | 28.358875862144 | 1990 | 28.55958001536 | 1989 | 28.595923962341 | 1988 | 28.81556623756 | 1987 | 28.956091894781 | 1986 | 28.902286658552 | 1985 | 28.890824529635 | 1984 | 28.904846163068 | 1983 | 28.826165954227 | 1982 | 28.964780593732 | 1981 | 28.966035391377 | 1980 | 28.992887672984 | 1979 | 29.012467278218 | 1978 | 29.050062152507 | 1977 | 28.986550672021 | 1976 | 28.985554821161 | 1975 | 29.069867556237 | 1974 | 29.138190826939 | 1973 | 29.15725291976 | 1972 | 29.31742535632 | 1971 | 29.448055742233 | 1970 | 30.10933004073 | 1969 | 30.380519802007 | 1968 | 30.432454549377 | 1967 | 30.618939462028 | 1966 | 30.758523767331 | 1965 | 31.052881009474 | 1964 | 31.260698209428 | 1963 | 31.507267292709 | 1962 | 31.667386060302 | 1961 | 31.760507537012 |
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