Year Percent 1999-01-01 5.16134 2000-01-01 5.05351 2001-01-01 3.34000 2002-01-01 3.38000 2003-01-01 3.54000 2004-01-01 3.78000 2005-01-01 4.14000 2006-01-01 4.21000 2007-01-01 4.60000 2008-01-01 4.65000 2009-01-01 5.30000 2010-01-01 5.43000 2011-01-01 5.52000 2012-01-01 6.08000 2013-01-01 6.08000 2014-01-01 6.63000 2015-01-01 6.59000 2016-01-01 6.76000