Year % 2002 15.68 2003 13.93 2004 13.95 2005 13.93 2006 13.44 2007 14.73 2008 14.81 2009 14.81 2012 3.14 2015 4.01 2016 7.21 2017 7.31 2020 9.93 2021 10.07