Year % 1993 58.49 1997 30.9 2000 43.71 2001 40.75 2002 40.28 2003 39.36 2005 34.81 2006 33.67 2007 32.61 2008 32.49 2009 28.44 2010 27.43 2011 26.32 2012 25.93 2014 18.31 2015 18.87 2016 18.87 2017 18.95 2019 18.93 2020 18.93 2021 20.21