Year Percent 2000-01-01 2.50 2001-01-01 3.03 2002-01-01 4.20 2003-01-01 3.87 2004-01-01 3.60 2005-01-01 3.59 2006-01-01 3.74 2007-01-01 3.65 2008-01-01 3.72 2009-01-01 3.92 2010-01-01 4.05 2011-01-01 4.42 2012-01-01 4.88 2013-01-01 5.30 2014-01-01 5.85 2015-01-01 6.64 2016-01-01 7.33