Year Percent 2000-01-01 30.06 2001-01-01 27.32 2002-01-01 21.97 2003-01-01 26.50 2004-01-01 28.05 2005-01-01 30.61 2006-01-01 42.13 2007-01-01 39.96 2008-01-01 22.05 2009-01-01 39.63 2010-01-01 42.07 2011-01-01 31.91 2012-01-01 38.84 2013-01-01 44.20 2014-01-01 49.44 2015-01-01 56.23 2016-01-01 55.67