Year % 1997 10.62 1998 8.69 1999 7.83 2000 7.19 2001 6.86 2002 7.46 2003 7.89 2004 7.63 2005 6.91 2006 7.6 2007 7.54 2008 7.24 2009 7.04 2010 6.93 2011 5.76 2012 6.13 2013 6.08 2015 5.41 2020 5.77 2021 6.43