Year Percent 2006 79.19156 2007 71.64914 2008 28.69283 2009 39.58301 2010 26.73591 2011 10.40326 2012 7.96981 2013 8.73891 2014 17.25651 2015 13.68356 2016 12.4608 2017 13.03538