Year % 2003 8.33 2004 8.25 2005 9.59 2006 10.78 2007 11.83 2008 11.1 2009 12.11 2010 12.7 2011 12.28 2012 12.34 2013 12.31 2014 12.85 2015 13.51 2016 13.95 2017 13.21 2018 11.96