Year Number 2007-01-01 632.6171 2008-01-01 567.3962 2009-01-01 509.5314 2010-01-01 508.4532 2011-01-01 495.7563 2012-01-01 514.6758 2013-01-01 546.9438 2014-01-01 570.8754 2015-01-01 598.3341 2016-01-01 618.1995 2017-01-01 641.1642