Year % 1996 15.3 1999 15.37 2000 13.68 2001 15.12 2002 13.49 2003 14.18 2006 15.75 2007 15.72 2008 15.7 2010 13.11 2011 13.18 2012 13.47 2013 13.48 2015 14.9 2016 15.8 2019 16.34