Year % 1996 39.24 1997 17.62 1998 16.31 1999 18.13 2000 15.99 2001 14.29 2002 15.57 2003 15.06 2007 13.98 2010 16 2011 12.48 2012 15.5 2015 12.59 2016 11.01 2021 12.38