| Year | Value | | 2020 | 54.62080267988 | | 2019 | 51.447254165614 | | 2018 | 49.553632772786 | | 2017 | 49.883507476525 | | 2016 | 47.110818261466 | | 2015 | 46.272544107848 | | 2014 | 45.952008752379 | | 2013 | 43.787489644913 | | 2012 | 40.780763101703 | | 2011 | 46.989011294706 | | 2010 | 50.460380629563 | | 2009 | 62.521750023432 | | 2008 | 65.679684227919 | | 2007 | 66.830775044685 | | 2006 | 62.944581604295 | | 2005 | 64.215381724522 | | 2004 | 69.508491614246 | | 2003 | 68.324104195225 | | 2002 | 71.519181948921 | | 2001 | 69.043523610218 |
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