| Year | Value | | 2022 | 47.963065131441 | | 2021 | 47.302672993185 | | 2020 | 49.476879353492 | | 2019 | 49.716914821577 | | 2018 | 48.534245551712 | | 2017 | 48.768385376566 | | 2016 | 49.061658122902 | | 2015 | 48.422805071194 | | 2014 | 47.357811795789 | | 2013 | 41.87980733989 | | 2012 | 41.670352625197 | | 2011 | 42.32684001769 | | 2010 | 44.544998987953 | | 2009 | 44.716457093867 | | 2008 | 43.309124972604 | | 2007 | 40.904778923861 | | 2006 | 43.75929994485 | | 2005 | 43.79407078294 | | 2004 | 43.943981663763 | | 2003 | 40.635245419441 | | 2002 | 40.067890413471 | | 2001 | 40.491821257649 | | 2000 | 38.183415146177 | | 1999 | 38.259658082684 | | 1998 | 36.495738986262 | | 1997 | 37.661364149618 | | 1996 | 37.698443409503 | | 1995 | 35.652575669567 | | 1994 | 34.763712543968 | | 1993 | 34.332038122652 | | 1992 | 31.230834873428 | | 1991 | 30.707891509277 |
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