Year % 1997 35.37 1999 37.98 2000 22.7 2001 21.73 2002 17.97 2003 16.63 2004 18.74 2005 19.28 2006 15.22 2007 16 2008 15.39 2009 13.87 2010 16.12 2012 14.98 2013 15.05 2018 46.42 2019 71.93 2020 18.43 2021 17.05