Year % 2003 30.2 2004 30.9 2005 30.6 2006 29.7 2007 28.9 2008 28.9 2009 27.5 2010 28.3 2011 28.7 2012 27.8 2013 27.5 2014 27.4 2015 27.3 2016 27.6 2017 26.7 2018 26.6 2019 26 2020 26.9 2021 27.6