Year % 1999 15.35 2001 11.99 2002 11.47 2003 10.61 2004 16.46 2005 12.04 2006 10.83 2007 8.3 2008 8.26 2009 9.74 2010 17.52 2011 12.8 2012 13.9 2013 16.05 2014 19.47 2015 22.43 2016 19.29 2017 21.44 2019 24.86 2020 23.18 2021 19.89