Year % 2000 4.615279999279901 2001 4.453042228699343 2002 4.346648797849011 2003 4.126156572112572 2004 3.952267026304517 2005 3.8107729580169427 2006 3.6219073365053194 2007 3.497519396213596 2008 3.3410192390431694 2009 3.2026896693130897 2010 3.0806950231091093 2011 2.9492745642222973 2012 2.8030734970674342 2013 2.687690976518066 2014 2.5809267421789124 2015 2.4891346516362196 2016 2.3653243612755306 2017 2.2655394824550554 2018 2.1529347478510306 2019 2.0742280205643553 2020 2.0165466169298636