Year % 2000 31.35278207029964 2001 31.05198526610129 2002 30.77506715847968 2003 30.444935999097222 2004 29.994578227568017 2005 29.575245660573206 2006 29.250659828654104 2007 28.879852226497377 2008 28.47955080439062 2009 28.105064052192542 2010 27.805058656905565 2011 27.604419662510384 2012 27.518721377534188 2013 27.466618286726376 2014 27.43023060136055 2015 27.41052350751001 2016 27.504759229645433 2017 27.579020353039187 2018 27.67864729491103 2019 27.756548664090325