Year Percent 2000-01-01 4.78 2001-01-01 4.98 2002-01-01 5.24 2003-01-01 5.46 2004-01-01 5.74 2005-01-01 6.13 2006-01-01 6.68 2007-01-01 7.21 2008-01-01 7.39 2009-01-01 8.44 2010-01-01 9.18 2011-01-01 9.62 2012-01-01 10.30 2013-01-01 10.47 2014-01-01 11.17 2015-01-01 11.29 2016-01-01 11.41