Year Percent 2003-01-01 1.25 2004-01-01 1.24 2005-01-01 1.45 2006-01-01 1.52 2007-01-01 1.72 2008-01-01 1.80 2009-01-01 2.19 2010-01-01 5.90 2011-01-01 6.28 2012-01-01 6.35 2013-01-01 6.58 2014-01-01 6.79 2015-01-01 6.64 2016-01-01 6.80