Year Percent 1993-01-01 16.2633 1994-01-01 17.7246 1995-01-01 15.2120 1996-01-01 11.2946 1997-01-01 12.6015 1998-01-01 14.0671 1999-01-01 14.4724 2000-01-01 16.0682 2001-01-01 18.9113 2002-01-01 20.6669 2003-01-01 22.8512 2004-01-01 25.9200 2005-01-01 29.1282 2006-01-01 32.9212 2007-01-01 31.8733 2008-01-01 32.4023 2009-01-01 39.8962 2010-01-01 44.4648 2011-01-01 39.4531 2012-01-01 36.4160 2013-01-01 37.7518 2014-01-01 39.4406 2015-01-01 40.5622 2016-01-01 42.5142