Year | Value | 2022 | 52.069089431153 | 2021 | 52.073157311133 | 2020 | 52.061720534302 | 2019 | 52.047869925589 | 2018 | 52.043189650325 | 2017 | 52.041372399824 | 2016 | 52.035061244143 | 2015 | 52.02377925329 | 2014 | 52.010363257493 | 2013 | 51.992631903361 | 2012 | 51.972442319219 | 2011 | 51.95187771342 | 2010 | 51.928466941948 | 2009 | 51.901981702995 | 2008 | 51.876406388672 | 2007 | 51.850654548351 | 2006 | 51.823563733324 | 2005 | 51.802732850599 | 2004 | 51.790276337384 | 2003 | 51.785536109646 | 2002 | 51.773997064118 | 2001 | 51.751479231649 | 2000 | 51.725830123722 | 1999 | 51.691285548882 | 1998 | 51.653708606568 | 1997 | 51.624933963945 | 1996 | 51.604351865266 | 1995 | 51.58715443932 | 1994 | 51.571734882686 | 1993 | 51.557765413932 | 1992 | 51.545036433553 | 1991 | 51.522351306856 | 1990 | 51.50343742101 | 1989 | 51.499716027209 | 1988 | 51.498397589837 | 1987 | 51.497073716085 | 1986 | 51.495206767901 | 1985 | 51.492687942939 | 1984 | 51.490638637252 | 1983 | 51.489358239897 | 1982 | 51.486520951822 | 1981 | 51.483769236469 | 1980 | 51.48884982789 | 1979 | 51.506678899895 | 1978 | 51.532560330411 | 1977 | 51.561804186017 | 1976 | 51.594881406526 | 1975 | 51.629214181654 | 1974 | 51.661695170019 | 1973 | 51.694767663576 | 1972 | 51.725894182949 | 1971 | 51.749757655979 | 1970 | 51.771083833215 | 1969 | 51.796248608661 | 1968 | 51.825953120117 | 1967 | 51.861079509796 | 1966 | 51.902267453194 | 1965 | 51.950017593828 | 1964 | 52.002863740178 | 1963 | 52.061000685603 | 1962 | 52.124036565693 | 1961 | 52.22699883213 | 1960 | 52.287822973564 |
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