Year Percent 1996-01-01 3.6047800000000003 1997-01-01 3.2703400000000000 1998-01-01 2.4628700000000000 1999-01-01 1.9129500000000000 2000-01-01 2.2763600000000000 2001-01-01 2.7310200000000000 2002-01-01 2.7662200000000000 2003-01-01 2.6195700000000000 2004-01-01 3.6140700000000000 2005-01-01 2.5135800000000000 2006-01-01 1.5231000000000000 2007-01-01 1.9048500000000000 2008-01-01 2.2903100000000000 2009-01-01 2.5877100000000000 2010-01-01 2.8361200000000000 2011-01-01 4.9365100000000000 2012-01-01 2.8767900000000000 2013-01-01 2.5233800000000000 2014-01-01 2.4490600000000000 2015-01-01 1.8037299999999998 2016-01-01 1.9270700000000000