Year Percent 1996-01-01 2.1741200000000003 1997-01-01 1.5240500000000000 1998-01-01 1.9777000000000000 1999-01-01 2.8497900000000000 2000-01-01 2.3437000000000000 2001-01-01 1.4552700000000000 2002-01-01 2.1083700000000000 2003-01-01 2.3103400000000000 2004-01-01 4.0676600000000000 2005-01-01 2.9566400000000000 2006-01-01 4.8102500000000000 2007-01-01 1.9026599999999998 2008-01-01 1.7098400000000002 2009-01-01 2.0581400000000003 2010-01-01 4.9775300000000010 2011-01-01 2.6657500000000000 2012-01-01 2.5108099999999998 2013-01-01 2.2331100000000000 2014-01-01 2.0597500000000000 2015-01-01 1.5191000000000000 2016-01-01 1.8640500000000000