Year % 2002 27.94 2003 28.1 2005 25.16 2006 15.1 2007 12.77 2008 11.69 2009 15.13 2010 14.05 2011 13.53 2012 18.76 2013 14.12 2014 14.95 2015 13.08 2016 12.52 2018 19.31 2019 19.02 2020 16.89 2021 16.41