Year Percent 2001-01-01 0.53 2002-01-01 2.41 2003-01-01 2.04 2004-01-01 1.73 2005-01-01 1.34 2006-01-01 1.36 2007-01-01 1.39 2008-01-01 1.34 2009-01-01 1.47 2010-01-01 1.42 2011-01-01 1.42 2012-01-01 1.45 2013-01-01 1.47 2014-01-01 1.49 2015-01-01 1.53 2016-01-01 1.58