Year Percent 2001-01-01 1.56 2002-01-01 1.71 2003-01-01 1.73 2004-01-01 1.77 2005-01-01 1.74 2006-01-01 1.68 2007-01-01 1.72 2008-01-01 1.69 2009-01-01 1.76 2010-01-01 1.85 2011-01-01 1.91 2012-01-01 1.91 2013-01-01 1.92 2014-01-01 1.91 2015-01-01 1.94