Year Number 2004-01-01 0.0151 2005-01-01 0.0151 2006-01-01 0.0151 2007-01-01 0.0159 2008-01-01 0.0222 2009-01-01 0.0262 2010-01-01 0.0302 2011-01-01 0.0341 2012-01-01 0.0341 2013-01-01 0.0461 2014-01-01 0.0548 2015-01-01 0.0580 2016-01-01 0.0611 2017-01-01 0.0627