Year % 2000 3.02129531760647 2001 2.84008097319135 2002 2.61539779684704 2003 2.49892214660867 2004 2.37435874211397 2005 2.27968637736096 2006 2.19939652579737 2007 2.14544771567526 2008 2.12662317066421 2009 2.02358591475919 2010 1.83963241854498 2011 1.70367537262879 2012 1.56948080400445 2013 1.32538613867373 2014 1.33401002456024 2015 1.25807418337706 2016 1.02313827654853 2017 0.939429610553174 2018 0.853959901706019 2019 0.801593512169048 2020 0.641200717433824