Year Percent 1996-01-01 9.7871800000000010 1997-01-01 5.8295800000000000 1998-01-01 6.2108400000000000 1999-01-01 5.1116199999999990 2000-01-01 4.4704000000000000 2001-01-01 3.7804500000000000 2002-01-01 3.6165000000000000 2003-01-01 3.2015700000000002 2004-01-01 3.3056600000000000 2005-01-01 3.1242000000000000 2006-01-01 3.2208900000000003 2007-01-01 3.3392300000000000 2008-01-01 2.8492500000000000 2009-01-01 2.0248500000000000 2010-01-01 1.5512600000000000 2011-01-01 2.0750200000000000 2012-01-01 2.0969000000000000 2013-01-01 2.3207400000000002 2014-01-01 2.0385700000000000 2015-01-01 1.2487900000000000 2016-01-01 2.5671900000000000