Year Percent 1999-01-01 0.24 2000-01-01 0.24 2001-01-01 0.24 2002-01-01 0.24 2003-01-01 0.24 2004-01-01 0.24 2005-01-01 2.70 2006-01-01 3.10 2007-01-01 2.57 2008-01-01 4.23 2009-01-01 4.43 2010-01-01 4.19 2011-01-01 3.70 2012-01-01 4.00 2013-01-01 4.53 2014-01-01 4.43