Year Percent 1998 61.29748 1999 64.40717 2000 68.46373 2001 73.58268 2002 71.96577 2003 65.09407 2004 60.92935 2005 54.10623 2006 52.11559 2007 52.29963 2008 50.38598 2009 54.98636 2010 53.95161 2011 50.93689 2012 44.1417 2013 44.05745 2014 43.86328