Year Percent 2002-01-01 0.004593 2003-01-01 0.460000 2004-01-01 0.880000 2005-01-01 1.240000 2006-01-01 3.070000 2007-01-01 3.520000 2008-01-01 3.800000 2009-01-01 4.950000 2010-01-01 5.840000 2011-01-01 6.040000 2012-01-01 6.290000 2013-01-01 6.420000 2014-01-01 6.810000 2015-01-01 6.920000 2016-01-01 6.950000