Year Percent 2000-01-01 1.72 2001-01-01 1.69 2002-01-01 1.69 2003-01-01 1.69 2004-01-01 2.04 2005-01-01 2.08 2006-01-01 2.00 2007-01-01 1.84 2008-01-01 1.65 2009-01-01 2.42 2010-01-01 2.78 2011-01-01 3.12 2012-01-01 3.23 2013-01-01 3.54 2014-01-01 3.84 2015-01-01 3.84