Year | Value | 2022 | 44.336001405228 | 2021 | 44.048597747364 | 2020 | 43.652499533033 | 2019 | 43.276940773099 | 2018 | 42.927995913731 | 2017 | 42.579788588635 | 2016 | 42.213685913875 | 2015 | 41.838702555758 | 2014 | 41.459924580457 | 2013 | 41.114117005126 | 2012 | 40.770188677332 | 2011 | 40.46673911284 | 2010 | 40.160702527454 | 2009 | 39.800565890615 | 2008 | 39.446384510288 | 2007 | 39.09879660511 | 2006 | 38.870175181727 | 2005 | 38.596901012768 | 2004 | 38.306980314028 | 2003 | 38.031210591638 | 2002 | 37.772266148799 | 2001 | 37.512867596317 | 2000 | 37.225310086216 | 1999 | 37.016508731107 | 1998 | 36.826538182048 | 1997 | 36.63947190408 | 1996 | 36.450254366105 | 1995 | 36.272795568572 | 1994 | 36.133668330908 | 1993 | 35.964667536963 | 1992 | 35.720520022482 | 1991 | 35.474147586751 | 1990 | 35.223374709051 | 1989 | 34.731452264453 | 1988 | 34.320626055466 | 1987 | 33.856289963858 | 1986 | 33.362845651627 | 1985 | 32.876048521196 | 1984 | 32.404119106483 | 1983 | 31.924570721138 | 1982 | 31.494286289352 | 1981 | 31.095439973059 | 1980 | 30.652157980009 | 1979 | 30.269093259391 | 1978 | 29.964522746227 | 1977 | 29.65157268034 | 1976 | 29.252661075185 | 1975 | 28.848858781487 | 1974 | 28.474618792269 | 1973 | 28.09457398936 | 1972 | 27.655979272675 | 1971 | 27.196085522639 | 1970 | 26.733797229436 | 1969 | 26.293843482666 | 1968 | 25.839918919716 | 1967 | 25.384243665268 | 1966 | 24.91874937371 | 1965 | 24.456895274166 | 1964 | 23.992282177303 | 1963 | 23.55293863592 | 1962 | 23.112387232977 | 1961 | 22.679455353347 | 1960 | 22.242569521635 |
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