Year % 1991 13.84 1994 8.54 1995 8.07 1996 12.07 1997 11.8 1998 11.92 1999 9.63 2000 13.62 2001 12.84 2002 12.42 2003 12.31 2004 6.95 2005 6.45 2006 5.45 2007 5.77 2008 6.44 2009 5.81 2010 6.6 2011 6.68 2012 6.38 2013 6.8 2014 6.57 2015 6.44 2016 5.88 2017 5.65 2018 5.73 2019 5.73 2020 5.67 2021 6.21