Year Percent 2002-01-01 30.17 2003-01-01 32.53 2004-01-01 33.40 2005-01-01 33.87 2006-01-01 36.15 2007-01-01 37.89 2008-01-01 38.48 2009-01-01 38.14 2010-01-01 39.67 2011-01-01 41.88 2012-01-01 50.16 2013-01-01 53.73 2014-01-01 58.03 2015-01-01 60.80 2016-01-01 63.16