Year | Value | 2022 | 49.010977084921 | 2021 | 48.983807926112 | 2020 | 48.957810022843 | 2019 | 48.932570442093 | 2018 | 48.905241093288 | 2017 | 48.876794915403 | 2016 | 48.847846313696 | 2015 | 48.818514933278 | 2014 | 48.788605459966 | 2013 | 48.758776144756 | 2012 | 48.801811164834 | 2011 | 48.926764255307 | 2010 | 49.069634073908 | 2009 | 49.230064503391 | 2008 | 49.405289150277 | 2007 | 49.528271372706 | 2006 | 49.595047950022 | 2005 | 49.670822876416 | 2004 | 49.754206154603 | 2003 | 49.842820409485 | 2002 | 49.935127828832 | 2001 | 50.03684160788 | 2000 | 50.089183574193 | 1999 | 50.082480764982 | 1998 | 50.077063290702 | 1997 | 50.07084553339 | 1996 | 50.061223246224 | 1995 | 50.049173626804 | 1994 | 50.035223875697 | 1993 | 50.018908712491 | 1992 | 50.00160649901 | 1991 | 49.985287726576 | 1990 | 49.970713255604 | 1989 | 49.959387020214 | 1988 | 49.949235169455 | 1987 | 49.938306685999 | 1986 | 49.9278368462 | 1985 | 49.918368632481 | 1984 | 49.910153773571 | 1983 | 49.903088238599 | 1982 | 49.896642249545 | 1981 | 49.889185125608 | 1980 | 49.879935806474 | 1979 | 49.86997049567 | 1978 | 49.859402188515 | 1977 | 49.848877421672 | 1976 | 49.839147766405 | 1975 | 49.8313160877 | 1974 | 49.824415985422 | 1973 | 49.816597928233 | 1972 | 49.807785283571 | 1971 | 49.796992461697 | 1970 | 49.783728005218 | 1969 | 49.766722506319 | 1968 | 49.747205822076 | 1967 | 49.725266148419 | 1966 | 49.701165279477 | 1965 | 49.676322283795 | 1964 | 49.651109476131 | 1963 | 49.625037035411 | 1962 | 49.59726301389 | 1961 | 49.568218665534 | 1960 | 49.538091637467 |
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