Year | Value | 2022 | 49.331410666464 | 2021 | 49.341253428734 | 2020 | 49.340535025065 | 2019 | 49.330772942649 | 2018 | 49.313039890046 | 2017 | 49.293035113979 | 2016 | 49.270385545406 | 2015 | 49.244590919797 | 2014 | 49.212644649162 | 2013 | 49.171166557936 | 2012 | 49.12372403415 | 2011 | 49.074264468804 | 2010 | 49.030007212963 | 2009 | 48.99149847524 | 2008 | 48.967024792809 | 2007 | 48.92246649172 | 2006 | 48.890620099353 | 2005 | 48.90099442507 | 2004 | 48.905501404262 | 2003 | 48.907141387736 | 2002 | 48.906601840069 | 2001 | 48.905186516647 | 2000 | 48.906200747512 | 1999 | 48.913196636518 | 1998 | 48.926819024002 | 1997 | 48.944148751457 | 1996 | 48.974936294753 | 1995 | 49.018990434207 | 1994 | 49.061990681666 | 1993 | 49.104046825261 | 1992 | 49.14487811991 | 1991 | 49.182266936101 | 1990 | 49.219370571491 | 1989 | 49.258074428538 | 1988 | 49.298248346199 | 1987 | 49.340500159217 | 1986 | 49.420861517069 | 1985 | 49.484288026761 | 1984 | 49.466810147292 | 1983 | 49.425059023179 | 1982 | 49.384002542329 | 1981 | 49.343316515843 | 1980 | 49.30118664007 | 1979 | 49.255725511481 | 1978 | 49.206475597819 | 1977 | 49.144298477714 | 1976 | 49.028315656939 | 1975 | 48.804124389482 | 1974 | 48.477541946402 | 1973 | 48.102596706148 | 1972 | 47.700962959857 | 1971 | 47.266904995759 | 1970 | 46.796569745799 | 1969 | 46.286145788732 | 1968 | 45.735011416675 | 1967 | 45.150899476888 | 1966 | 44.807234628723 | 1965 | 44.715189137662 | 1964 | 44.605167732539 | 1963 | 44.482399788417 | 1962 | 44.349487243861 | 1961 | 44.207545062065 | 1960 | 44.056147826488 |
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