Year % 1989 10.64 1993 9.83 1995 9.51 1996 7.99 1997 6.86 1998 5.11 1999 4.8 2000 4.67 2001 5.11 2002 4.75 2003 4.33 2004 4.12 2005 4.12 2006 3.99 2007 3.98 2008 3.99 2009 3.93 2010 3.18 2011 3.1 2012 2.98 2013 2.81 2014 2.77 2015 2.86 2016 2.65 2017 1.64 2018 1.65 2019 1.49 2020 1.47 2021 1.65