Year % 2004 27.1 2005 29.3 2006 25.8 2007 24.7 2008 26 2009 27.2 2010 27.3 2011 26.5 2012 26.1 2013 28.1 2014 26.1 2015 26.5 2016 25.2 2017 23.2 2018 25 2019 23.2 2020 24.2 2021 24.1