Year % 1999 12.67 2000 11.87 2001 7.41 2002 6.45 2003 6.44 2004 6.4 2005 5.95 2006 5.65 2007 8.54 2008 7.37 2009 5.83 2010 5.69 2011 6.81 2012 6.81 2013 4.54 2014 3.88 2015 4.54 2016 4.55 2017 22.35 2018 17.78 2019 7.7 2020 4.74 2021 4.78