Year Percent 1999 41.67946 2000 38.16763 2001 32.87158 2002 35.22849 2003 29.3534 2004 37.90133 2006 37.50974 2007 31.9959 2008 30.94795 2009 24.57943 2011 16.63108 2012 24.2171 2016 25.20772