Year Percent 2001-01-01 1.3326300000000000 2002-01-01 1.3585100000000000 2003-01-01 1.3901900000000000 2004-01-01 1.5294400000000000 2005-01-01 1.6966900000000003 2006-01-01 1.4326000000000000 2007-01-01 1.8908200000000002 2008-01-01 2.0369200000000003 2009-01-01 1.6855200000000001 2010-01-01 2.0622400000000000 2011-01-01 1.8205900000000002 2012-01-01 2.5298500000000000 2013-01-01 2.3913100000000000 2014-01-01 2.3467400000000000 2015-01-01 2.4332900000000000