Year % 1990 13.22 1993 14.75 1995 16.77 1996 11.39 1997 5.86 1998 5.35 1999 5.02 2000 4.46 2001 4.38 2002 4.33 2003 4.82 2004 4.3 2005 4.37 2006 4.41 2007 3.92 2008 3.92 2009 3.97 2010 3.44 2011 4.07 2012 2.67 2013 4.07 2014 4.11 2015 2.92 2016 2.89 2017 3.34 2018 3.42 2019 7.77 2020 3.29 2021 3.27