Year % 1992 12.09 1993 8.91 1996 7.31 1997 6.26 1998 5.25 1999 4.47 2000 3.56 2001 4.48 2002 4.9 2003 5.52 2004 5.41 2005 4.38 2006 4.22 2007 4.34 2008 3.05 2009 2.69 2010 3.02 2011 2.66 2012 2.94 2013 2.99 2014 2.9 2015 2.96 2016 3.1 2017 3.16 2019 3.01 2020 2.79 2021 2.94