Year Percent 1998-01-01 3.6000000000000000 1999-01-01 5.8000000000000000 2000-01-01 7.8000000000000000 2001-01-01 10.0000000000000000 2002-01-01 12.4000000000000000 2003-01-01 12.4000000000000000 2004-01-01 17.7000000000000000 2005-01-01 16.4000000000000000 2006-01-01 13.5000000000000000 2007-01-01 10.1000000000000000 2008-01-01 7.5000000000000000 2009-01-01 6.0000000000000000 2010-01-01 4.3000000000000000 2011-01-01 3.7569300000000000 2012-01-01 3.7869800000000002 2013-01-01 3.9655300000000000 2014-01-01 4.0080400000000000 2015-01-01 4.1952900000000000 2016-01-01 4.8790800000000000