Year Number 2007-01-01 0.7440 2008-01-01 0.8280 2009-01-01 0.9914 2010-01-01 1.2028 2011-01-01 1.5037 2012-01-01 1.7502 2013-01-01 2.0198 2014-01-01 2.2764 2015-01-01 2.5616