Year % 1996 20.89 1999 17.64 2000 11.72 2001 17.53 2002 11.96 2003 11.9 2006 10.02 2007 10.03 2008 10.07 2010 8.95 2011 11.06 2012 10.54 2013 10.27 2015 9.88 2016 10.01 2019 9.24