Year % 1996 28.32933 1997 32.92605 1998 28.32933 1999 28.32933 2000 53.11828 2001 29.4182 2002 32.2737 2003 32.60213 2004 32.60879 2005 31.49311 2006 28.4727 2007 26.18385 2008 27.12736 2010 26.4992 2011 31.29876 2012 32.11539 2013 31.69595 2015 26.59621 2016 25.42605 2017 20.22178 2018 20.2167 2020 19.76218 2021 18.5791