Year Percent 2001-01-01 3.68 2002-01-01 4.77 2003-01-01 4.83 2004-01-01 4.76 2005-01-01 4.84 2006-01-01 4.19 2007-01-01 3.92 2008-01-01 3.74 2009-01-01 3.90 2010-01-01 3.51 2011-01-01 3.11 2012-01-01 2.86 2013-01-01 2.65 2014-01-01 2.61 2015-01-01 2.89 2016-01-01 2.98