Year Percent 2000-01-01 1.28 2001-01-01 2.49 2002-01-01 3.91 2003-01-01 5.33 2004-01-01 6.80 2005-01-01 8.80 2006-01-01 11.03 2007-01-01 11.80 2008-01-01 10.91 2009-01-01 13.15 2010-01-01 15.32 2011-01-01 14.54 2012-01-01 16.77 2013-01-01 18.20 2014-01-01 8.74 2015-01-01 7.93 2016-01-01 8.41