Year Percent 2002 4.0029 2003 1.7524 2005 2.0927 2006 1.8605 2007 2.4083 2008 2.6292 2009 3.8273 2010 2.6394 2011 2.5591 2012 1.5379 2014 3.0311 2015 4.0453 2016 6.302 2017 7.5669