Year Percent 2003-01-01 2.86560 2004-01-01 2.80705 2005-01-01 2.57032 2006-01-01 2.48855 2007-01-01 2.37458 2008-01-01 3.59116 2009-01-01 7.61460 2010-01-01 7.51580 2011-01-01 8.40519 2012-01-01 10.67770 2013-01-01 10.45240 2014-01-01 13.98610 2015-01-01 13.57910 2016-01-01 13.63880