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 1.22 2007 1.08 2008 2.14 2009 2.15 2010 2.08 2012 1.93 2013 1.93 2018 1.23 2019 1.28 2020 2.25 2021 2.24