Year % 1996 41.15 1997 25.14 1998 20.94 1999 25.34 2000 21.7 2001 19 2002 17.82 2003 16.28 2007 18.6 2010 16.48 2011 12.09 2012 17.17 2015 12.97 2016 9.78 2021 17.97