Year Percent 1999-01-01 3.600 2000-01-01 3.200 2001-01-01 3.500 2002-01-01 3.200 2003-01-01 4.600 2004-01-01 4.900 2005-01-01 5.200 2006-01-01 4.800 2007-01-01 4.600 2008-01-01 4.000 2009-01-01 4.600 2010-01-01 5.275 2011-01-01 4.900 2012-01-01 4.825 2013-01-01 5.000 2014-01-01 5.150 2015-01-01 5.000 2016-01-01 5.150 2017-01-01 5.200