Year | Value | 2021 | 46.486709653648 | 2020 | 46.490420044215 | 2019 | 46.398305084746 | 2018 | 46.333824613117 | 2017 | 46.329403095063 | 2016 | 46.250921149595 | 2015 | 46.167096536478 | 2014 | 45.845615327929 | 2013 | 46.011422254974 | 2012 | 47.190493736183 | 2011 | 46.86809137804 | 2010 | 46.53647752395 | 2009 | 46.333824613117 | 2008 | 46.966209372986 | 2007 | 47.104318202744 | 2006 | 47.776857221762 | 2005 | 48.462812960236 | 2004 | 49.006987863185 | 2003 | 48.9657074561 | 2002 | 48.943014705882 | 2001 | 49.697188827624 | 2000 | 50.456476543433 | 1999 | 51.333273072404 | 1998 | 51.02594233029 | 1997 | 56.069782156739 | 1996 | 55.717255717256 | 1995 | 55.717255717256 | 1994 | 55.672060019886 | 1993 | 55.328572719877 | 1992 | 55.626864322516 | 1991 | 55.690138298834 | 1990 | 55.672060019886 | 1989 | 55.753412275151 | 1988 | 55.699177438308 | 1987 | 55.735333996204 | 1986 | 55.735333996204 | 1985 | 55.762451414625 | 1984 | 55.789568833047 | 1983 | 55.834764530417 | 1982 | 55.879960227786 | 1981 | 55.852842809365 | 1980 | 55.870921088312 | 1979 | 56.09689957516 | 1978 | 56.14209527253 | 1977 | 56.09689957516 | 1976 | 56.024586459369 | 1975 | 53.828075567206 | 1974 | 54.578324143542 | 1973 | 54.072132333002 | 1972 | 54.433697911959 | 1971 | 54.316189098798 | 1970 | 54.325228238272 | 1969 | 54.433697911959 | 1968 | 53.159179246136 | 1967 | 52.996474735605 | 1966 | 52.445087227696 | 1965 | 52.363734972431 | 1964 | 52.173913043478 | 1963 | 51.459821025038 | 1962 | 51.387507909247 | 1961 | 51.27903823556 |
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