| Year | Value | | 2022 | 0.75509690410269 | | 2021 | 0.66261733848702 | | 2020 | 0.70550082023953 | | 2019 | 0.69471890671796 | | 2018 | 0.73370651739304 | | 2017 | 0.75259097311274 | | 2016 | 0.8322746862645 | | 2015 | 0.89758700635953 | | 2014 | 1.3565475935217 | | 2013 | 1.3906604859534 | | 2012 | 1.3988511100761 | | 2011 | 1.5758149600974 | | 2010 | 1.5056247059327 | | 2009 | 0.84902090625296 | | 2008 | 1.123182132964 | | 2007 | 1.4602229648142 | | 2006 | 5.1702592939706 | | 2005 | 6.4606741573034 | | 2004 | 9.698726157579 | | 2003 | 8.6059439811845 | | 2002 | 7.2244662435084 | | 2001 | 6.9784119698824 | | 2000 | 7.6923076923077 | | 1999 | 5.375157629256 | | 1998 | 12.286282306163 | | 1997 | 12.64724116553 | | 1996 | 6.6951099442074 | | 1995 | 4.1002277904328 |
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