Year Percent 2003 25.39761 2004 14.2312 2005 6.46153 2006 4.11035 2007 6.62903 2008 6.41224 2009 9.48833 2010 6.56979 2011 5.84272 2012 10.41526 2013 15.22987 2014 21.60274 2015 29.89435 2016 31.53679 2017 27.58391