| Year | Value | | 2022 | 46.555163910893 | | 2021 | 46.874675808346 | | 2020 | 47.003581634611 | | 2019 | 48.0740164416 | | 2018 | 48.027840137879 | | 2017 | 48.432712629847 | | 2016 | 48.873740946353 | | 2015 | 48.995731324726 | | 2014 | 46.702060657977 | | 2013 | 46.346271478853 | | 2012 | 45.153049915768 | | 2011 | 42.51610594348 | | 2010 | 39.794460010414 | | 2009 | 38.72560532744 | | 2008 | 38.568534436025 | | 2007 | 38.445392609477 | | 2006 | 38.741371457153 | | 2005 | 38.19580084444 | | 2004 | 35.895839208251 | | 2003 | 34.525012845341 | | 2002 | 36.142219380057 | | 2001 | 35.956493434205 | | 2000 | 32.834800939112 | | 1999 | 33.083297770362 | | 1998 | 32.855728174712 | | 1997 | 35.451789883268 | | 1996 | 34.212173207078 | | 1995 | 33.851253275857 | | 1994 | 33.80479379305 | | 1993 | 33.799834799422 | | 1992 | 33.650402262425 | | 1991 | 33.63140497831 |
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