Year Percent 2000 44.69748 2001 45.68379 2002 45.95542 2003 40.89077 2004 41.18204 2005 43.54412 2006 44.51019 2007 45.50385 2008 48.72933 2009 45.65543 2010 49.69072 2011 56.35033 2012 59.57921 2013 58.76402 2014 62.57787 2015 57.57941 2016 54.04133 2017 50.23535