Year % 1995 8.06 1997 6.58 1998 6.04 1999 5.15 2000 5.14 2001 5.8 2002 5.73 2003 5.96 2004 4.85 2005 5.97 2006 5.44 2007 4.75 2008 3.06 2009 3.15 2010 2.66 2011 2.53 2012 2.44 2013 1.93 2014 1.6 2015 1.52 2020 1.53 2021 1.78