Year % 2000 28.5 2001 28.6 2002 28.6 2003 28.5 2004 28.4 2005 28.1 2006 27.8 2007 27.6 2008 27.2 2009 27.2 2010 27 2011 26.9 2012 26.7 2013 26.4 2014 26.1 2015 25.9 2016 25.6 2017 25.2 2018 24.9 2019 24.5