Year | Value | 2022 | 24.970892460545 | 2021 | 26.556712633175 | 2020 | 24.345497159606 | 2019 | 25.542712225502 | 2018 | 25.238340618623 | 2017 | 24.722837132723 | 2016 | 24.164816706821 | 2015 | 23.68698848449 | 2014 | 23.003675608107 | 2013 | 22.389648940306 | 2012 | 22.188741226983 | 2011 | 22.540963044361 | 2010 | 21.790385997938 | 2009 | 21.171148205273 | 2008 | 23.375977954617 | 2007 | 24.667279413215 | 2006 | 23.94923200045 | 2005 | 23.168670831656 | 2004 | 23.207296941377 | 2003 | 22.249117328172 | 2002 | 22.724390455196 | 2001 | 22.85126411965 | 2000 | 22.945092683101 | 1999 | 23.08670031215 | 1998 | 23.232977099795 | 1997 | 22.978137516382 | 1996 | 22.384168294507 | 1995 | 22.582958121081 | 1994 | 21.58215333519 | 1993 | 21.39246366503 | 1992 | 21.894742459518 | 1991 | 22.611751652029 | 1990 | 23.424743089829 | 1989 | 23.230958675593 | 1988 | 22.855417162248 | 1987 | 21.840606846353 | 1986 | 22.163472467233 | 1985 | 21.186023911942 | 1984 | 21.014703826527 | 1983 | 20.448590478768 | 1982 | 20.258196350612 | 1981 | 20.599254899206 | 1980 | 22.372668822907 | 1979 | 23.454856599947 | 1978 | 23.642408789862 | 1977 | 23.18641023184 | 1976 | 23.373893240726 | 1975 | 23.250825126779 |
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