Year Percent 1998 36.08043 1999 24.20848 2000 15.7419 2001 17.22572 2002 20.80131 2003 22.34201 2004 22.78564 2005 21.89344 2006 22.2978 2007 22.63517 2008 19.04264 2009 19.6311 2010 18.87649 2012 18.43656 2013 17.40966 2014 5.58524