| Year | Value | | 2024 | 47.424320977096 | | 2023 | 47.509420855935 | | 2022 | 47.623719673913 | | 2021 | 47.770781743743 | | 2020 | 47.08931101073 | | 2019 | 47.751914489141 | | 2018 | 48.058520262179 | | 2017 | 48.522283835311 | | 2016 | 49.132074813592 | | 2015 | 49.738912779702 | | 2014 | 50.491589690779 | | 2013 | 50.651904158505 | | 2012 | 50.827207382599 | | 2011 | 51.094401374645 | | 2010 | 51.344712075291 | | 2009 | 51.272685244173 | | 2008 | 51.328596307481 | | 2007 | 51.286220010069 | | 2006 | 51.266270779991 | | 2005 | 51.20263982019 | | 2004 | 51.062166219197 | | 2003 | 50.928437955971 | | 2002 | 50.79056877441 | | 2001 | 50.647676203071 | | 2000 | 50.514000477349 | | 1999 | 50.235502631727 | | 1998 | 49.995195426365 | | 1997 | 49.902380756354 | | 1996 | 49.695794321879 | | 1995 | 49.419010845371 | | 1994 | 49.150949541106 | | 1993 | 48.939522316496 | | 1992 | 48.774865040678 | | 1991 | 48.586005314686 |
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