Year % 1995 22.36 1998 17.59 1999 19.98 2000 19.98 2001 20.1 2002 28.22 2003 17.66 2004 12.13 2005 10.67 2006 11.56 2007 9.83 2008 9.35 2009 8.66 2010 10.9 2011 9.97 2012 9.99 2013 9.55 2014 8.94 2015 8.43 2016 7.64 2017 6.71 2018 6.59 2019 6.07