Year % 1995 51.29 1998 46.51 1999 24.77 2000 24.21 2001 20.63 2002 17.49 2003 17.12 2004 16.36 2005 14.74 2006 14.89 2007 14.99 2008 14.22 2009 14.78 2010 14.87 2011 14.46 2012 14.28 2013 14.74 2014 13.9 2015 13.02 2016 12.71 2018 12.81 2019 12.8 2020 12.04 2021 11.96