Year % 1996 22.46 1999 21.5 2000 15.9 2001 17.36 2002 17.4 2003 17.18 2006 14.32 2007 13.06 2008 12.25 2009 15.88 2010 13.11 2011 12.88 2012 14.97 2013 14.95 2014 12.46 2015 12.51 2016 12.59 2017 22.85 2018 22.89 2019 22.86 2020 10.87