Year % 1997 13.17 1999 13.15 2000 2.43 2001 2.43 2002 2.48 2003 1.75 2004 1.51 2005 1.44 2006 1.23 2007 1.08 2008 2.14 2009 2.15 2010 2.09 2012 1.93 2013 1.93 2018 1.26 2019 1.31 2020 2.25 2021 2.26