Year Percent 1998-01-01 6.7000000000000000 1999-01-01 10.5000000000000000 2000-01-01 9.2000000000000000 2001-01-01 29.3000000000000000 2002-01-01 12.7000000000000000 2003-01-01 11.5000000000000000 2004-01-01 6.5000000000000000 2005-01-01 5.0000000000000000 2006-01-01 3.9000000000000000 2007-01-01 3.3000000000000000 2008-01-01 3.4000000000000000 2009-01-01 5.0000000000000000 2010-01-01 3.4895900000000000 2011-01-01 2.5763200000000000 2012-01-01 2.7433700000000000 2013-01-01 2.6362700000000000 2014-01-01 2.7418299999999998 2015-01-01 2.9877200000000000 2016-01-01 3.1096800000000000