Year % 2001 10.69 2002 7.88 2005 6.03 2007 6.28 2008 6.15 2009 6.1 2010 5.65 2011 5.76 2013 5.92 2015 6.26 2016 6.48 2017 6.49 2018 6.49 2021 6.78