| Year | Value | | 2022 | 57.79133497746 | | 2021 | 55.760501159045 | | 2020 | 54.478772080112 | | 2019 | 57.074575771899 | | 2018 | 56.98822973314 | | 2017 | 56.373600466602 | | 2016 | 55.76585199017 | | 2015 | 56.231449368205 | | 2014 | 56.298202406582 | | 2013 | 55.421997641687 | | 2012 | 52.209063903782 | | 2011 | 53.394449872973 | | 2010 | 52.662597869922 | | 2009 | 49.290744027118 | | 2008 | 51.925710859856 | | 2007 | 49.005142626755 | | 2006 | 47.367748750045 | | 2005 | 47.071187934029 | | 2004 | 43.883669251979 | | 2003 | 45.17949052919 | | 2002 | 43.387243815978 | | 2001 | 44.913608685327 | | 2000 | 46.272059811232 | | 1999 | 47.493382022796 | | 1998 | 46.445516522431 | | 1997 | 46.324794634251 | | 1996 | 46.053494671583 | | 1995 | 45.868919904177 | | 1994 | 45.576731270543 | | 1993 | 45.524254689687 | | 1992 | 45.539671462185 | | 1991 | 45.584646534034 |
|