Year Percent 2000-01-01 3.30 2001-01-01 3.59 2002-01-01 4.17 2003-01-01 4.95 2004-01-01 5.63 2005-01-01 6.17 2006-01-01 6.88 2007-01-01 7.54 2008-01-01 7.41 2009-01-01 8.75 2010-01-01 8.90 2011-01-01 8.56 2012-01-01 9.54 2013-01-01 9.58 2014-01-01 10.39 2015-01-01 11.77 2016-01-01 13.34