Year | Value | 2022 | 49.261281652177 | 2021 | 49.248888114655 | 2020 | 49.259407007134 | 2019 | 49.248690621723 | 2018 | 49.223733655396 | 2017 | 49.198347213379 | 2016 | 49.172446004029 | 2015 | 49.145508114086 | 2014 | 49.119678636349 | 2013 | 49.108083730053 | 2012 | 49.104529369764 | 2011 | 49.091710579429 | 2010 | 49.063594358546 | 2009 | 49.023586793085 | 2008 | 48.982987369278 | 2007 | 48.943844979444 | 2006 | 48.904652824917 | 2005 | 48.86376248977 | 2004 | 48.82540189313 | 2003 | 48.788246101351 | 2002 | 48.75015749885 | 2001 | 48.712400330157 | 2000 | 48.686127892241 | 1999 | 48.670489358773 | 1998 | 48.654698493243 | 1997 | 48.640272383307 | 1996 | 48.626046084895 | 1995 | 48.610452474286 | 1994 | 48.592251248922 | 1993 | 48.571274347034 | 1992 | 48.554353252986 | 1991 | 48.540971383904 | 1990 | 48.535402504875 | 1989 | 48.534154411822 | 1988 | 48.528001139735 | 1987 | 48.521143590199 | 1986 | 48.511202910311 | 1985 | 48.502629406214 | 1984 | 48.495332152394 | 1983 | 48.484768741302 | 1982 | 48.475333094805 | 1981 | 48.467969390796 | 1980 | 48.457973955362 | 1979 | 48.447384550428 | 1978 | 48.43812755183 | 1977 | 48.430247762852 | 1976 | 48.425492593014 | 1975 | 48.422601280806 | 1974 | 48.416567921876 | 1973 | 48.41132447521 | 1972 | 48.411763959488 | 1971 | 48.419286655626 | 1970 | 48.431604582562 | 1969 | 48.44547848416 | 1968 | 48.459816016194 | 1967 | 48.470083526599 | 1966 | 48.477564028461 | 1965 | 48.480798703045 | 1964 | 48.479267574349 | 1963 | 48.479218581507 | 1962 | 48.483402210454 | 1961 | 48.489034685575 | 1960 | 48.505067739331 |
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