Year % 1999 11.98 2001 11.43 2002 13.05 2003 12.82 2004 13.14 2005 12.2 2006 3.46 2007 1.38 2008 1.37 2009 1.23 2010 1.16 2011 1.71 2012 1.21 2013 1 2015 0.56 2016 1.12 2020 0.48 2021 0.54